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(function () { | |
var | |
documentElement = document.documentElement, | |
viewportFontSize, viewportHeight, viewportIsPortrait, viewportMax, viewportMin, viewportWidth; | |
function getViewportFontSize() { | |
var | |
body = documentElement.appendChild(document.createElement('body')), | |
iframe = document.createElement('iframe'), | |
iframeDocument; | |
iframe.style.cssText = 'clip:rect(0 0 0 0);position:absolute'; | |
body.appendChild(iframe); | |
iframeDocument = iframe.contentWindow.document; | |
iframeDocument.write('<div style=height:1em;overflow:hidden>'); | |
iframeDocument.close(); | |
viewportFontSize = iframeDocument.body.lastChild.clientHeight; | |
documentElement.removeChild(body); | |
} | |
function getViewportSize() { | |
viewportHeight = Math.max(documentElement.clientHeight, documentElement.offsetHeight); | |
viewportWidth = Math.max(documentElement.clientWidth, documentElement.offsetWidth); | |
viewportMax = Math.max(viewportHeight, viewportWidth); | |
viewportMin = Math.min(viewportHeight, viewportWidth); | |
viewportIsPortrait = viewportHeight > viewportWidth; | |
} | |
function replace() { | |
var args = arguments, index = 0, string = args[0]; | |
while (++index in args) { | |
string = string.replace(args[index], args[++index]); | |
} | |
return string; | |
} | |
function computeCSSValue(length, unit) { | |
return length * replace(unit, | |
/cm/, 37.7952, | |
/r?em/, viewportFontSize, | |
/in/, 96, | |
/mm/, 3.77952, | |
/pc/, 16, | |
/pt/, 4 / 3, | |
/px/, 1, | |
/vh/, viewportHeight, | |
/vmax/, viewportMax, | |
/vmin/, viewportMin, | |
/vw/, viewportWidth | |
); | |
} | |
function evaluateMediaQuery(query) { | |
return new Function('e', 'try{return ' + replace(String(query || 1).toLowerCase(), | |
// ignore `only` | |
/^only\s+/g, '', | |
// wrap `not` | |
/not([^)]+)/g, '!($1)', | |
// interpret `all`, `portrait`, and `screen` as truthy | |
/all|portrait|screen/g, 1, | |
// interpret `landscape`, `print` and `speech` as falsey | |
/landscape|print|speech/g, 0, | |
// interpret `and` | |
/\band\b/g, '&&', | |
// interpret `,` | |
/,/g, '||', | |
// interpret `min-` as >= | |
/min-([a-z-\s]+):/g, 'e.$1>=', | |
// interpret `min-` as <= | |
/max-([a-z-\s]+):/g, 'e.$1<=', | |
// interpret others as == | |
/([a-z-\s]+):/g, 'e.$1==', | |
// calc for calc not for mq ;-) | |
/calc([^)]+)/g, '($1)', | |
// interpret css values | |
/(\d+)([a-z]+)/g, function (match, length, unit) { | |
return computeCSSValue(length, unit); | |
} | |
// make eval safer?!? | |
,/^(?!(e.width|e.height|e.orienation|[0-9\.&=|><\+\-\*\(\)\/])).*/ig, '' | |
) + '}catch(e){}')({ | |
height: viewportHeight, | |
orientation: viewportIsPortrait, | |
width: viewportWidth | |
}); | |
} | |
})(); |
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