javascriptでメディアクエリを実行

javascript

window.matchMedia || (window.matchMedia = function() {"use strict";
    // For browsers that support matchMedium api such as IE 9 and webkit
    var styleMedia = (window.styleMedia || window.media);

    // For those that don't support matchMedium
    if (!styleMedia) {
        var style = document.createElement('style'), script = document.getElementsByTagName('script')[0], info = null;

        style.type = 'text/css';
        style.id = 'matchmediajs-test';

        script.parentNode.insertBefore(style, script);

        // 'style.currentStyle' is used by IE <= 8 and 'window.getComputedStyle' for all other browsers
        info = ('getComputedStyle' in window) && window.getComputedStyle(style, null) || style.currentStyle;

        styleMedia = {
            matchMedium : function(media) {
                var text = '@media ' + media + '{ #matchmediajs-test { width: 1px; } }';

                // 'style.styleSheet' is used by IE <= 8 and 'style.textContent' for all other browsers
                if (style.styleSheet) {
                    style.styleSheet.cssText = text;
                } else {
                    style.textContent = text;
                }

                // Test if media query is true or false
                return info.width === '1px';
            }
        };
    }

    return function(media) {
        return {
            matches : styleMedia.matchMedium(media || 'all'),
            media : media || 'all'
        };
    };
}());

how use

    if (window.matchMedia) {
        if (window.matchMedia('only screen and (max-width: 480px)').matches) {
            /*
             * 処理を記述
             */
        }