fontAvailable.js

/* fontAvailable Prototype Plugin, v1.0
 *
 * Copyright (c) 2009, Jonathan Blanchet
 * Licensed under the MIT License
 * http://github.com/jblanche/prototype-fontavailable/tree/master
 * 
 * Based on jQuery fontAvailable plugin:
 * http://code.google.com/p/jquery-fontavailable/
 * and Edward H. Trager and gCSSCapabilities plugin : 
 * http://eyegene.ophthy.med.umich.edu/fontface/javascript/gCSSCapabilities.js
 */

(function($) {
	var element;

    $.fontAvailable = function(fontName) {
        var width, height;

        // prepare element, and append to DOM
        if(!element) {
            element = $( document.createElement( 'span' ))
                .css( 'visibility', 'hidden' )
                .css( 'position', 'absolute' )
                .css( 'top', '-10000px' )
                .css( 'left', '-10000px' )
                .html( 'abcdefghijklmnopqrstuvwxyz' )
                .appendTo( document.body );
        }

        // get the width/height of element after applying a fake font
        width = element
            .css('font-family', '__FAKEFONT__')
            .width();
        height = element.height();

        // set test font
        element.css('font-family', fontName);

        return width !== element.width() || height !== element.height();
    }


		$.fontFaceAvailable = function(){
			var n=document.styleSheets.length;
			if(n){
				for(var i=0;i<n;i++){
					if( _checkStyleSheetforFontFaceRule( document.styleSheets[i] )){
						self.supportsWebFonts=true;
						break;
					}
				}
			}
			
			$.checkForFontFaceRule = function (stylesheet) {
				var n=stylesheet.cssRules.length;
				if(!n) return false;
				
				for(var i=0;i<n;i++){
					if(stylesheet.cssRules[i].type===self.FONT_FACE_RULE){
						var text = stylesheet.cssRules[i].cssText;
						text = text.replace(/^\s*@font-face\s*{/,"");
						text = text.replace(/}/,"");
						alert(text);
						var vals = text.split(";");
						for(var j=0;j<vals.length;j++){
							var pair = vals[j].split(":");
							if(pair[0].match(/font-family/)){
								pair[1] = pair[1].replace(/^\s*(\S*(\s+\S+)*)\s*$/, "$1");
								if(pair[1].length){
									return true;
								}
							}
						}
					}
				}
				
				return false;
			}
			
			$.isCufonNeeded = function(fontName) {
				!fontAvailable(fontName) && !fontFaceAvailable() ; 
			}
		}

})(jQuery);