Strikethrough
View on Wikipediafrom Wikipedia
Look up strikethrough or Appendix:Strikethrough in Wiktionary, the free dictionary.
Strikethrough, or strikeout, is a typographical presentation of words with a horizontal line through their middle. Less common alternative forms of strikethrough are an X or a forward slash typed over each letter.[1]
In medieval manuscripts, where strikethrough appears as a red line over the otherwise black text, the purpose is to highlight the text, giving it emphasis. In modern texts, the purpose is the opposite; it indicates removed text. Contrary to censored or redacted texts, the words remain readable.
Appearance
[edit]Strikethrough primarily appears as a horizontal line across the middle of words. This appearance is the easiest to achieve by hand, as it only requires one continuous stroke with a pen, pencil, or other writing instruments. Less common forms of strikethrough include drawing an X (cross) or / (solidus) over each letter of the word. To strike long words or phrases, this method is cumbersome to produce by hand, but may be the preferred method for single letters, where the horizontal line does not produce the necessary visibility, and could be missed.
On personal computers, double strikethrough is an option in some word processors, spreadsheets, presentation software, and graphics software, e.g., in Microsoft Office, Collabora Online and LibreOffice. In Japan, double strikethrough is conventionally used because in complex kanji, a single strikethrough may be missed or confused with a stroke in the character. Otherwise, there is no generally agreed meaning of double strikethrough.
Uses
[edit]In modern prose, however, strikethrough is primarily used to mark text as a mistake or to be removed. Word processors capable of tracking changes use strikethrough to on deleted words.
Historically, however, strikethrough was not even the primary way to mark errors. Errors were more commonly marked by placing dots under letters to be ignored (Latin: punctum delens).[2] In medieval manuscripts such as the Domesday Book, "strikethrough" of text with red ink often functions as highlighting similar to modern underline.[3]
Computer representations
[edit]Word Processors
[edit]Wordstar supported the "strikeout" decoration since version 3.0 in 1982, although the functionality may have been present in earlier versions.[4] Wordstar was launched in 1978. It dominated the personal computer market as the most popular word processing program until 1985, when WordPerfect gained dominance. All word processors with functionality beyond basic editing include strikeout, though the prefer the term "strikethrough".
HTML and CSS
[edit]Early versions of the Hypertext Markup Language (HTML) specify the <strike> or <s> tags for rendering text with strikethrough. These tags, however, are purely decorative. In 1999, the HTML standard version 4.01 deprecated them in favor of the <del> tag, a semantic element for marking deleted text. Web browser and other user agents often render the contents of this tag with strikethrough.[5][6] In the HTML5 draft, the <s> is redefined as a semantic tag that marks its text that as no longer correct. The <del> remains unchanged and still specifies deleted text.[7][8]
Since HTML5 has done away with purely decorative strikethrough tags, the Cascading Style Sheets (CSS) language is in charge of decoration and formatting. A CSS user agent renders the text with strikethrough when the text-decoration CSS property has a line-through value. For example:
<span style="text-decoration: line-through;">ABCD efghi</span>
...renders as:
ABCD efghi
The <s> and <del> tags already carry the aforementioned strikethrough definition, but also attach their semantic properties ("not longer correct" and "deleted") to the text.
Other markup symbols
[edit]- BB Code, a markup language used on many web forums, specifies the
[s]and[strike]tags for decorating text with strikethrough. - GitHub-flavored Markdown uses double tilde
~~to wrap around text for strikethrough.[9] - Google Chat or WhatsApp render text surrounded with the
~(tilde) character as struck out.[10]
Unicode
[edit]Combining characters
[edit]In plain text scenarios where markup cannot be used, Unicode offers a number of combining characters that achieve similar effects.
The "combining long stroke overlay" (U+0336) results in a stroke across text (may or may not be unbroken depending on the typeface used):
- A̶B̶C̶D̶ ̶e̶f̶g̶h̶i̶
while the "combining short stroke overlay" (U+0335) results in individually struck out characters:
- A̵B̵C̵D̵ ̵e̵f̵g̵h̵i̵
Similarly, the "combining short solidus overlay" (U+0337) results in diagonally struck out letters:
- A̷B̷C̷D̷ ̷e̷f̷g̷h̷i̷
as does the "combining long solidus overlay" (U+0338), which produces longer diagonal strokes:
- A̸B̸C̸D̸ ̸e̸f̸g̸h̸i̸
Specific struck-through characters
[edit]A number of characters that have the visual appearance of struck-through characters exist in Unicode, including:
These usually have specific functions (for example, in the Latin Extended-A character set) or representations and are not intended for general use. However, they are not precomposed characters and have neither canonical nor compatibility decompositions. This issue has created security considerations since "precomposed" characters like U+019F and sequences like U+004F U+0335 or U+004F U+0336 often cause visual confusion (compare ⟨Ɵ⟩, ⟨O̵⟩ and ⟨O̶⟩). Unicode has acknowledged this issue and has proposed a standardized method for counteraction.[11][12]
For slashed letters in an orthography, unitary letters are provided by Unicode. The diacritics are used in generic applications, such as math operators which systematically use the solidus overlay to indicate negation.
Research
[edit]Since at least 2014, researchers in the area of optical character recognition have attempted to solve the problem of recognizing struck-out text in handwritten documents.[13][14]
See also
[edit]Notes
[edit]References
[edit]- ^ "Strikethrough". eyemagazine. Retrieved 9 September 2024.
- ^ Hackett, M.B. (1970). The original statutes of Cambridge University : the text and its history (Digitally printed version, re-issue. ed.). Cambridge: Cambridge Eng. University Press. p. 185. ISBN 9780521070768.
- ^ See, e.g., this image from the British National Archives' Focus on the Domesday Book.
- ^ "Exploring the WordStar file format". TechnicallyWeWrite.com. Retrieved 11 September 2024.
- ^ 15.2.1 Font style elements: the TT, I, B, BIG, SMALL, STRIKE, S, and U elements, HTML 4.01 Specification: Alignment, font styles, and horizontal rules, W3C. 24 December 1999.
- ^ 9.4 Marking document changes: The INS and DEL elements HTML 4.01 Specification: Text – Paragraphs, Lines, and Phrases, W3C. 24 December 1999.
- ^ 4.5.5 The s element Archived 2015-08-01 at the Wayback Machine HTML5, W3C Last Call Working Draft. 17 June 2014.
- ^ 4.6.2 The del element HTML5, W3C Last Call Working Draft 17 June 2014
- ^ "GitHub Flavored Markdown".
- ^ "Add formatting to your Google Chat messages - Computer - Google Chat Help". support.google.com. Retrieved 1 March 2024.
- ^ The Unicode Consortium, The Unicode Standard, Chapter 2, Page 44, Non-decomposition of Overlaid Diacritics
- ^ The Unicode Consortium, Unicode Technical Standard #39: Unicode Security Mechanisms, chapter Confusable Detection
- ^ Adak, Chandranath; Chaudhuri, Bidyut B. (2014). "An Approach of Strike-Through Text Identification from Handwritten Documents". 2014 14th International Conference on Frontiers in Handwriting Recognition. pp. 643–648. doi:10.1109/ICFHR.2014.113. ISBN 978-1-4799-4334-0. S2CID 5364504.
- ^ Chaudhuri, Bidyut B.; Adak, Chandranath (2017). "An approach for detecting and cleaning of struck-out handwritten text". Pattern Recognition. 61: 282–294. Bibcode:2017PatRe..61..282C. doi:10.1016/j.patcog.2016.07.032.
| Page | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Paragraph | |||||||||||
| Character |
| ||||||||||
| Typeface classifications |
| ||||||||||
| Punctuation (List) | |||||||||||
| Typesetting | |||||||||||
| Typographic units | |||||||||||
| Digital typography | |||||||||||
| Typography in other writing systems | |||||||||||
| Related articles | |||||||||||
| Related template | |||||||||||
Strikethrough
View on Grokipediafrom Grokipedia
<s> element for rendering strikethrough to signify outdated information, while the <del> element specifically marks deleted content in versioned documents; both are supported across modern browsers.[2] Additionally, markup languages like Markdown use double tildes (Overview
Definition
Strikethrough is a typographical technique that applies a horizontal line through the center of text characters to signify deletion, cancellation, or ironic emphasis while preserving the original content for reference.[7][4] This method allows editors and readers to see both the intended correction and the prior version, facilitating transparency in revisions without complete erasure.[4] Visually, strikethrough differs from other text formats such as underline, which positions a line beneath the baseline of letters, or bold, which thickens the strokes for prominence; instead, it overlays a straight or slightly oblique line at the approximate midline of the characters, effectively "crossing out" the text.[7] For instance, in plain text, the phrase "This is strikethrough text" appears unmodified, whereas "This isHistory
The practice of strikethrough, a horizontal line drawn through text to indicate deletion or cancellation, originated in medieval scribal traditions as a method for marking errors in manuscripts. Scribes on parchment would employ various deletion techniques, including punctum delens—dots, small crosses, underlining, or strikethrough lines—to signal text for removal without fully erasing it, preserving legibility for potential review or correction.[9] This approach allowed for efficient editing while maintaining the integrity of the original material, often using colored inks for emphasis in illuminated manuscripts.[3] In the 19th century, as printing industrialized, strikethrough evolved into a standard proofreading mark applied to galley proofs, where a looped line through text (known as the "dele" mark) denoted material to be deleted. This adaptation of scribal deletion methods ensured accuracy in the mechanical reproduction of texts, marking a shift from manual erasure to systematic typographic oversight.[10][11] In the 19th and 20th centuries, strikethrough gained widespread use in professional fields such as journalism and legal documentation, influenced by the rise of typewriters. Typewriters enabled practical corrections through overtyping or dedicated mechanisms like correction tape, while manual strikethrough with pen became common for marking changes in newsroom editing and contract amendments.[12] In legal contexts, redlining practices—originating from manual markup with red ink—formalized strikethrough for tracking changes in drafts, often with added notations for validation.[13] This era solidified strikethrough as a tool for transparency in iterative document revision. The 21st-century digital shift transformed strikethrough into a software-rendered feature in word processors and design tools, enabling precise, non-destructive editing. Early applications like Microsoft Word incorporated it as a font attribute, evolving from print-era habits to track changes functionalities.[4] Concurrently, publications such as Strikethrough: Typographic Messages of Protest (2022) have documented its historical role in U.S. graphic design for activism, tracing typographic uses of deletion lines in protest graphics from the 1800s to contemporary digital expressions of dissent.[14]Uses
Editing and Correction
In traditional editing and proofreading, strikethrough serves as a standard method to indicate deletions in manuscripts, drafts, and typeset pages, allowing editors to mark errors or unwanted content for removal while preserving the original text for reference and review. This approach avoids complete erasure, enabling authors and collaborators to track the evolution of the document and understand the rationale behind changes, which is particularly valuable in fields like academic writing and legal revisions where edit history must be auditable. For instance, in manuscript preparation, a horizontal line is drawn through the text to signal its excision, often accompanied by a marginal note such as "delete" to clarify the instruction.[15][4] In collaborative digital environments, strikethrough is integral to features like Microsoft Word's Track Changes, where it denotes deleted text, displaying it with a strikethrough line—typically in red and attributed to the specific editor—alongside timestamps for accountability. This functionality ensures that revisions are visible without disrupting the document's flow, facilitating efficient review in professional settings such as academic papers or legal documents. Insertions, by contrast, are commonly underlined or highlighted in a different color, creating a clear visual distinction that highlights the full scope of edits.[16] Proofreading systems like those outlined in The Chicago Manual of Style integrate strikethrough as a core symbol for content removal in final versions, differentiating it from other marks such as underlining for insertions or carets for additions, thereby streamlining the transition from draft to publication. In legal and regulatory contexts, this practice is similarly employed to amend documents, with strikethrough applied to excised clauses while maintaining the unaltered original for verification, as seen in amendment protocols for statutes. Such standardized use underscores strikethrough's role in maintaining transparency and precision during revision processes.[15]Communication and Emphasis
In digital communication, strikethrough serves as a pragmatic tool to convey sarcasm and humor, particularly on platforms like Twitter (now X) and Reddit, where it highlights irony or self-deprecation without fully erasing the original text. For instance, a user might write "I'm totallyCommercial and Symbolic Applications
In e-commerce, strikethrough formatting is commonly employed to highlight discounts by displaying the original price crossed out alongside the reduced price, such asTechnical Representations
Typography and Document Software
In traditional print typography, strikethrough was achieved through manual typesetting techniques, such as placing thin horizontal rules or overlays across composed text to simulate a crossing line, a method rooted in earlier practices like those seen in medieval manuscripts where text was struck out for corrections.[24] Modern digital typography has integrated built-in support for strikethrough in design software, exemplified by Adobe InDesign, where users select text and apply the feature via the Character panel, allowing customization of line weight, offset from the baseline, style type, color, and tint for precise rendering.[25] The evolution from manual overstrike methods on typewriters in the mid-20th century—where corrections involved typing a line over erroneous text—to graphical user interface (GUI) formatting in the 1980s marked a significant shift, with software like WordPerfect introducing dedicated strikeout attributes compatible with emerging laser printers for cleaner, non-overlapping deletions.[26][27] In contemporary word processors, strikethrough is applied via keystroke shortcuts or menus; for instance, in Microsoft Word, users can open the Font dialog with Ctrl+D, select the text, and check the Strikethrough option to toggle a single horizontal line through the characters for visibility without obscuring readability.[28] This feature integrates with stylesheets, enabling consistent application across documents through character or paragraph styles that define the line's attributes, such as single or double lines, while preserving the underlying text for editing.[29] Document standards like PDF and DOCX ensure strikethrough preservation across platforms. In PDF format, strikethrough can be embedded as a text markup, as implemented in tools like Adobe Acrobat for cross-document compatibility.[30] Similarly, the DOCX format, based on OOXML, uses the<w:strike> element to specify single-line strikethrough on run-level content, allowing variations in line thickness and color via associated styling, while a separate <w:dstrike> element handles double strikethrough for enhanced markup needs.[31] These standards facilitate seamless transfer of formatted documents, maintaining the strikethrough's visual and semantic integrity during export or import.
Web and Markup Languages
In web development, strikethrough text is commonly implemented using HTML elements that convey semantic meaning or visual styling. The<s> element renders text with a horizontal line through it, indicating content that is no longer relevant or accurate, such as outdated information. The deprecated <strike> element similarly applies a strikethrough but is obsolete in modern HTML standards, though browsers continue to support it for backward compatibility. For marking deletions in documents, the <del> element is preferred, which typically renders as strikethrough and supports a datetime attribute to specify when the deletion occurred, enhancing semantic precision in versioned content.
CSS provides flexible control over strikethrough appearance through the text-decoration shorthand property, where line-through sets the line type, and additional values like color or thickness can be specified (e.g., text-decoration: line-through [red](/page/Red) solid 2px;). This approach allows customization of line style via text-decoration-style (e.g., solid, wavy, or double) and thickness via text-decoration-thickness, overriding default browser rendering and ensuring consistency across elements. For older browsers like Internet Explorer, vendor-specific properties such as -ms-text-decoration may be needed, though HTML5 standards have minimized such requirements.
In lightweight markup languages, strikethrough is achieved through simple delimiters. Markdown uses double tildes to enclose text (e.g., ~~strikethrough~~), which renders as strikethrough in processors like GitHub Flavored Markdown. Similarly, LaTeX implements strikethrough via the ulem package, where \sout{text} draws a line through the content after including \usepackage{ulem} in the preamble.[32]
Browser support for these features is universal in modern environments, with the <s> and <del> elements fully compatible since HTML5 across major browsers like Chrome (version 1), Firefox (version 1), and Safari (version 1). For accessibility, ARIA roles such as role="deletion" can be applied to custom strikethrough implementations, informing screen readers that content is marked as removed, especially when semantic HTML elements are unavailable.[33]
Unicode Encoding
In Unicode, strikethrough is primarily achieved through combining diacritical marks that overlay a horizontal stroke on base characters. The key character for this is U+0336 COMBINING LONG STROKE OVERLAY, introduced in Unicode 1.1, which applies a continuous horizontal line across one or more preceding characters, such as in the sequence for "A̶" (U+0041 followed by U+0336).[6] This mark is designed to connect on the left and right when multiple are applied sequentially, facilitating unbroken strikethrough over words or phrases, though its rendering depends on font support for proper joining.[6] Limitations arise in font rendering, where inconsistent glyph positioning can result in discontinuous lines or gaps, particularly in variable-width fonts or across complex scripts.[34] For specific precomposed characters incorporating strikethrough, Unicode includes dedicated glyphs in certain blocks, such as U+1D7A LATIN SMALL LETTER TH WITH STRIKETHROUGH in the Phonetic Extensions block (added in Unicode 4.1). This represents the voiceless interdental fricative with an obligatory horizontal bar through the digraph, distinguishing it from diagonal variants and avoiding reliance on combining marks.[35] Mathematical contexts may use related overlays like U+0335 COMBINING SHORT STROKE OVERLAY for shorter, non-connecting strikes on individual symbols, or U+0338 COMBINING LONG SOLIDUS OVERLAY for slash-like effects, though these are not true horizontal strikethroughs.[6] Support for strikethrough in emoji and symbols expanded with Unicode 6.0 (2010), enabling combining overlays on base emoji characters for crossed-out effects in messaging applications, such as applying U+0336 to regional indicator symbols (U+1F1E6–U+1F1FF) to denote negated or canceled flags (e.g., a struck-through country code).[34] However, this remains non-standardized for full text sequences in emoji, relying on platform-specific rendering. Compatibility issues persist due to variable support across devices and fonts; older systems or limited Unicode implementations may fail to display combining overlays correctly, leading to fallback mechanisms like CSS text-decoration: line-through in web contexts for consistent rendering.[35]Variants and Alternatives
Multiple Strikethroughs
Double strikethrough consists of two parallel horizontal lines drawn through text, serving as a variation of the standard single-line strikethrough for heightened visual emphasis.[1] In some professional contexts, it may indicate changes in wording.[1] Extensions to triple or more strikethrough lines are less standardized but appear in stylistic applications within graphic design and technical documentation to convey escalating levels of obsolescence or rejection.[36] These multiple-line variants amplify the deletion signal, often used where single or double lines might not sufficiently underscore the text's irrelevance. In web development, multiple lines can be approximated by layering text-decoration properties, though precise control varies by browser support. In Unicode, multiple strikethroughs are typically rendered by repeatedly applying the combining character U+0336 (COMBINING LONG STROKE OVERLAY) to each base character, allowing for stacked lines without dedicated code points for doubles or triples.[37] However, this method faces rendering challenges, as font engines may cause overlaps or misalignments when stacking multiple overlays, particularly in variable-width fonts or across different platforms.[38] While uncommon in daily communication, multiple strikethrough variants find niche use in fields requiring precise notation of revisions, such as contract drafting or specialized diagramming, where they help track iterative changes without fully erasing content.[39]Substitute Symbols
In informal and constrained environments where standard strikethrough formatting is unavailable, symbols such as the letter X or a forward slash (/) are employed as substitutes to indicate cancellation or deletion of text. The letter X is frequently used in handwritten notes and checklists to cross out text for quick cancellation, serving as a visual indicator of completion or invalidation. This practice extends to historical voting systems, where an X has been associated with marking ballots, including to void or negate selections.[40] In plain text environments, such as emails or programming interfaces without rich formatting, a forward slash can be used in specific contexts, for example, in European handwriting conventions, a forward slash is commonly drawn through the digit 7 to distinguish it from the number 1, preventing misreading in mathematical or numerical contexts.[41] Additionally, Unicode provides slashthrough effects using combining characters like U+0337 (COMBINING SHORT SOLIDUS OVERLAY) or U+0338 (COMBINING LONG SLASH OVERLAY) to approximate diagonal strikethrough on individual characters.[6] These substitute symbols are particularly advantageous in informal notes or constrained settings, where they enable rapid editing without additional software; however, their diagonal or intersecting nature often leads to less precise rendering and potential readability issues in dense text, unlike the uniform horizontal line of standard strikethrough.[42]Research and Implications
Cognitive and Perceptual Studies
Research in cognitive psychology has examined the perceptual processing of strikethrough text, revealing that such formatting introduces visual complexity that can increase cognitive load during reading. For instance, users with cognitive disabilities may face heightened processing demands when interpreting the significance of crossed-out content, as it requires additional mental effort to discern intent without disrupting overall text flow.[43] General studies on text formatting indicate that modifications can alter eye movements and attention allocation, potentially slowing reading speed by drawing focus to marked elements, though specific quantitative impacts vary by context.[44] In educational settings, strikethrough serves as a tool for highlighting errors in written feedback, aiding comprehension and learning by contrasting incorrect and corrected versions without complete erasure. A study on computer-mediated corrective feedback in English as a foreign language (EFL) writing classes found that using track changes—which employs strikethrough for deletions—significantly improved learners' writing accuracy compared to traditional marginal feedback methods. Participants receiving strikethrough-based feedback demonstrated greater uptake of corrections, fostering deeper understanding of grammatical and structural errors through visible revision traces. This approach supports retention by encouraging learners to mentally note the rationale behind changes, enhancing long-term skill development.[45] Behavioral economics research highlights strikethrough's role in pricing psychology, where it influences decision-making by signaling discounts and perceived value. In a theoretical model supported by empirical analysis, firms use strikethrough prices to convey product quality, particularly when costs decline over time, such as in technology markets. By displaying a higher past price crossed out alongside the current lower price, sellers separate high-quality offerings from low-quality ones, as consumers infer superior value from the implied reduction; this reduces uncertainty and boosts purchase intent when prior beliefs about quality are low. The strategy proves effective in high-cost-decline scenarios, leading to higher demand for signaled products without incentivizing low-quality mimicry.[46] Despite these benefits, overuse of strikethrough can create visual clutter, impairing document clarity and overall readability. Usability studies on display clutter demonstrate that excessive formatting elements disrupt information flow in the brain, particularly in visual processing pathways, resulting in reduced comprehension and increased cognitive strain. Researchers emphasize moderation to maintain usability, as dense visual modifications hinder efficient scanning and interpretation.[47][48]Accessibility and Usability
Screen readers provide varying levels of support for strikethrough text, particularly when implemented using semantic HTML elements like<del>, which indicates deleted or struck-through content. Popular screen readers such as NVDA and JAWS typically announce <del> as "deleted text," enabling visually impaired users to understand the semantic intent without relying on visual cues.[49] However, support is inconsistent across tools; for instance, VoiceOver on iOS may not always verbalize the strikethrough, potentially leading to missed context.[50] Additionally, using Unicode combining characters to achieve strikethrough can cause misreads in screen readers, as these diacritical marks are often ignored or fragmented, disrupting the flow for assistive technology users.[51]
Usability guidelines emphasize ensuring strikethrough enhances rather than hinders comprehension, especially for users with low vision. The Web Content Accessibility Guidelines (WCAG) 2.1 require a minimum contrast ratio of 4.5:1 for text and images of text, which applies to ensure readability of strikethrough-formatted content.[52] Experts recommend avoiding strikethrough for critical information, as it can confuse users with low vision who may overlook or misinterpret the crossed-out content amid visual noise.[53] Instead, pairing it with textual descriptions, per WCAG Technique G117, conveys the same information programmatically to support diverse assistive needs.[54]
In handwritten document analysis, particularly for historical archives, optical character recognition (OCR) and AI systems face challenges in detecting and processing struck-out words, which can obscure writer identification and content restoration. A 2021 study introduced algorithms for generating synthetic handwritten text with realistic strikethrough simulations to train OCR models, improving detection accuracy in degraded manuscripts by up to 15% through data augmentation techniques.[55] Cleaning algorithms, such as those using image inpainting and stroke removal, enable better writer identification in archives by isolating underlying text; for example, a method combining convolutional neural networks with morphological operations successfully restored struck-out segments in 19th-century documents, aiding paleographic analysis.[56]
Modern implications for strikethrough accessibility extend to mobile apps and AI-assisted editing, where post-2020 standards prioritize intuitive interactions. In mobile interfaces, touch-friendly toggles for applying strikethrough—such as targets meeting the minimum 24x24 CSS pixels size with clear haptic feedback—comply with WCAG 2.2 Success Criterion 2.5.8 for reducing errors among users with motor impairments during editing tasks.[57] Evolving standards since 2020, including WCAG 2.2's emphasis on adaptive content, guide AI-assisted editing tools to automatically generate accessible alternatives, like verbal announcements of strikethrough changes in real-time collaboration apps, ensuring compliance for dynamically generated documents.[58]