root / drupal7 / sites / all / themes / adaptivetheme / at_core / scripts / matchMedia.addListener.js @ a08833bd
| 1 | 74f6bef0 | Assos Assos | /*! matchMedia() polyfill addListener/removeListener extension. Author & copyright (c) 2012: Scott Jehl. Dual MIT/BSD license */
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| 2 | (function(){
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| 3 | a08833bd | Assos Assos | // Bail out for browsers that have addListener support
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| 4 | if (window.matchMedia && window.matchMedia('all').addListener) { |
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| 5 | return false; |
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| 6 | } |
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| 7 | |||
| 8 | var localMatchMedia = window.matchMedia,
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| 9 | hasMediaQueries = localMatchMedia('only all').matches,
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| 10 | isListening = false,
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| 11 | timeoutID = 0, // setTimeout for debouncing 'handleChange' |
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| 12 | queries = [], // Contains each 'mql' and associated 'listeners' if 'addListener' is used
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| 13 | handleChange = function(evt) { |
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| 14 | // Debounce
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| 15 | clearTimeout(timeoutID); |
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| 16 | |||
| 17 | timeoutID = setTimeout(function() {
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| 18 | for (var i = 0, il = queries.length; i < il; i++) { |
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| 19 | var mql = queries[i].mql,
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| 20 | listeners = queries[i].listeners || [], |
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| 21 | matches = localMatchMedia(mql.media).matches; |
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| 22 | |||
| 23 | // Update mql.matches value and call listeners
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| 24 | // Fire listeners only if transitioning to or from matched state
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| 25 | if (matches !== mql.matches) {
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| 26 | mql.matches = matches; |
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| 27 | |||
| 28 | for (var j = 0, jl = listeners.length; j < jl; j++) { |
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| 29 | listeners[j].call(window, mql); |
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| 30 | } |
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| 31 | } |
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| 32 | } |
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| 33 | }, 30);
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| 34 | }; |
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| 35 | |||
| 36 | window.matchMedia = function(media) { |
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| 37 | var mql = localMatchMedia(media),
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| 38 | listeners = [], |
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| 39 | index = 0;
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| 40 | |||
| 41 | mql.addListener = function(listener) { |
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| 42 | // Changes would not occur to css media type so return now (Affects IE <= 8)
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| 43 | if (!hasMediaQueries) {
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| 44 | return;
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| 45 | } |
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| 46 | |||
| 47 | // Set up 'resize' listener for browsers that support CSS3 media queries (Not for IE <= 8)
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| 48 | // There should only ever be 1 resize listener running for performance
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| 49 | if (!isListening) {
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| 50 | isListening = true;
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| 51 | window.addEventListener('resize', handleChange, true); |
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| 52 | } |
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| 53 | |||
| 54 | // Push object only if it has not been pushed already
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| 55 | if (index === 0) { |
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| 56 | index = queries.push({
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| 57 | mql : mql,
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| 58 | listeners : listeners
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| 59 | }); |
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| 60 | } |
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| 61 | |||
| 62 | listeners.push(listener); |
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| 63 | }; |
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| 64 | |||
| 65 | mql.removeListener = function(listener) { |
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| 66 | for (var i = 0, il = listeners.length; i < il; i++){ |
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| 67 | if (listeners[i] === listener){
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| 68 | listeners.splice(i, 1);
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| 69 | } |
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| 70 | } |
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| 71 | }; |
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| 72 | |||
| 73 | return mql;
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| 74 | }; |
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| 75 | 74f6bef0 | Assos Assos | }()); |