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Chofoteddy
Asked: 2020-12-17 20:25:46 +0800 CST 2020-12-17 20:25:46 +0800 CST

Double quotes or single quotes in HTML?

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Personally I like to use double quotes on HTML attributes/values, but I have seen codes where the use of single quotes is what predominates over the document and even! some without quotation marks.

<input type="text" name="age" />
<input type='text' name='age' />
<input type=text name=age />

Apart from knowing the compatibility of its use with browsers, I would like to know which of these forms to use and why? are there any functional implications that affect performance?

Example:

In many programming languages; The difference between single and double quotes to declare text strings is the interpolation, but it is unnecessary to discuss that about HTML since we know it does not fall into that category. But is there any behavior that alters the way the data is presented?

html

1 Answers

  1. Best Answer

    Summary

    Double quotes are used since in the early days of the markup language ( SGML ), authors could make use of special characters (which were sometimes difficult, if not impossible, to enter via the keyboard) just by typing their reference, p. e.g.:

    • "&amp;lt;"represents the sign <.
    • "&amp;gt;"represents the sign >.
    • "&amp;quot;"represents the sign ".
    • "&amp;#229;"(in decimal) represents the letter awith a small circle on it.
    • Among others...

    In short, like some programming languages, they had rich functionality compared to single quotes.

    Source: W3C - HTML4 .

    Explanation

    The official W3C document (on HTML5 syntax) states that the use of the attribute-value pair with single quotes, double quotes or even without quotes is perfectly correct; Sure! each with certain rules.

    Attribute value without quotes

    The attribute name, followed by one or more space characters, followed by a single U+300D EQUAL SIGN character, followed by one or more space characters, followed by the attribute value, which, in addition to the requirements provided..., you must dispense with any literal space character , any U+0022 QUOTATION MARK (single quotes), U+0027 APOSTROPHE (apostrophe), U+003D EQUALS SIGN (equals symbol), U+003C LESS-THAN SIGN, U+003E GREATER-THAN SIGN, or U+0060 GRAVE ACCENT, and must not be an empty string.

    Attribute value with single quotes

    The attribute name, followed by one or more space characters, followed by a single character U+300D EQUAL SIGN, followed by one or more space characters, followed by U+0027 APOSTROPHE, followed of the attribute value, which, in addition to the requirements provided..., must dispense with any character of U+0027 APOSTROPHE (literal apostrophe) and finally followed by another U+0027 APOSTROPHE (apostrophe).

    Attribute value with double quotes

    The attribute name, followed by one or more space characters, followed by a single U+300D EQUAL SIGN character, followed by one or more space characters, followed by U+0022 QUOTATION MARK , followed by the value of the attribute, which, in addition to the requirements provided..., must dispense with any character of U+0022 QUOTATION MARK (English quotation mark) and finally followed by another U+0022 QUOTATION MARK (English quotation mark).

    Derived from all this (and probably custom) the W3C uses double quotes or without quotes in its examples , it is for convenience and sometimes good practice to promote the same thing that the official documentation urges you to do based on its examples, do what Otherwise it is like trying to cut down a tree, going against the grain of the wood.

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