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67 lines
1.7 KiB
JavaScript
67 lines
1.7 KiB
JavaScript
define(['ModernizrProto', 'cssomPrefixes'], function(ModernizrProto, prefixes) {
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/**
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* atRule returns a given CSS property at-rule (eg @keyframes), possibly in
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* some prefixed form, or false, in the case of an unsupported rule
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*
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* @memberOf Modernizr
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* @name Modernizr.atRule
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* @optionName Modernizr.atRule()
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* @optionProp atRule
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* @access public
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* @function atRule
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* @param {string} prop - String name of the @-rule to test for
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* @returns {string|boolean} The string representing the (possibly prefixed)
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* valid version of the @-rule, or `false` when it is unsupported.
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* @example
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* ```js
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* var keyframes = Modernizr.atRule('@keyframes');
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*
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* if (keyframes) {
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* // keyframes are supported
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* // could be `@-webkit-keyframes` or `@keyframes`
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* } else {
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* // keyframes === `false`
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* }
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* ```
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*/
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var atRule = function(prop) {
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var length = prefixes.length;
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var cssrule = window.CSSRule;
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var rule;
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if (typeof cssrule === 'undefined') {
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return undefined;
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}
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if (!prop) {
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return false;
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}
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// remove literal @ from beginning of provided property
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prop = prop.replace(/^@/, '');
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// CSSRules use underscores instead of dashes
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rule = prop.replace(/-/g, '_').toUpperCase() + '_RULE';
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if (rule in cssrule) {
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return '@' + prop;
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}
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for (var i = 0; i < length; i++) {
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// prefixes gives us something like -o-, and we want O_
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var prefix = prefixes[i];
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var thisRule = prefix.toUpperCase() + '_' + rule;
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if (thisRule in cssrule) {
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return '@-' + prefix.toLowerCase() + '-' + prop;
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}
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}
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return false;
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};
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ModernizrProto.atRule = atRule;
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return atRule;
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});
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