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Forked from wad3g/loadCSS.js
Created November 27, 2019 01:58
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Load CSS async via loadCSS.js
<script>
/*! loadCSS: load a CSS file asynchronously. [c]2016 @scottjehl, Filament Group, Inc. Licensed MIT */
(function(w){
"use strict";
/* exported loadCSS */
var loadCSS = function( href, before, media ){
// Arguments explained:
// `href` [REQUIRED] is the URL for your CSS file.
// `before` [OPTIONAL] is the element the script should use as a reference for injecting our stylesheet <link> before
// By default, loadCSS attempts to inject the link after the last stylesheet or script in the DOM. However, you might desire a more specific location in your document.
// `media` [OPTIONAL] is the media type or query of the stylesheet. By default it will be 'all'
var doc = w.document;
var ss = doc.createElement( "link" );
var ref;
if( before ){
ref = before;
}
else {
var refs = ( doc.body || doc.getElementsByTagName( "head" )[ 0 ] ).childNodes;
ref = refs[ refs.length - 1];
}
var sheets = doc.styleSheets;
ss.rel = "stylesheet";
ss.href = href;
// temporarily set media to something inapplicable to ensure it'll fetch without blocking render
ss.media = "only x";
// wait until body is defined before injecting link. This ensures a non-blocking load in IE11.
function ready( cb ){
if( doc.body ){
return cb();
}
setTimeout(function(){
ready( cb );
});
}
// Inject link
// Note: the ternary preserves the existing behavior of "before" argument, but we could choose to change the argument to "after" in a later release and standardize on ref.nextSibling for all refs
// Note: `insertBefore` is used instead of `appendChild`, for safety re: http://www.paulirish.com/2011/surefire-dom-element-insertion/
ready( function(){
ref.parentNode.insertBefore( ss, ( before ? ref : ref.nextSibling ) );
});
// A method (exposed on return object for external use) that mimics onload by polling until document.styleSheets until it includes the new sheet.
var onloadcssdefined = function( cb ){
var resolvedHref = ss.href;
var i = sheets.length;
while( i-- ){
if( sheets[ i ].href === resolvedHref ){
return cb();
}
}
setTimeout(function() {
onloadcssdefined( cb );
});
};
function loadCB(){
if( ss.addEventListener ){
ss.removeEventListener( "load", loadCB );
}
ss.media = media || "all";
}
// once loaded, set link's media back to `all` so that the stylesheet applies once it loads
if( ss.addEventListener ){
ss.addEventListener( "load", loadCB);
}
ss.onloadcssdefined = onloadcssdefined;
onloadcssdefined( loadCB );
return ss;
};
// commonjs
if( typeof exports !== "undefined" ){
exports.loadCSS = loadCSS;
}
else {
w.loadCSS = loadCSS;
}
}( typeof global !== "undefined" ? global : this ));
loadCSS( "https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.5.0/css/font-awesome.min.css" );
</script>
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