/**
 * JavaScript code to detect available availability of a 
 * particular font in a browser using JavaScript and CSS. 
 * 
 * Author : Lalit Patel
 * Website: http://www.lalit.org/lab/jsoncookies
 * License: Creative Commons Attribution-ShareAlike 2.5
 *          http://creativecommons.org/licenses/by-sa/2.5/
 * Version: 0.15 
 *          changed comparision font to serif from sans-serif, 
 *          as in FF3.0 font of child element didn't fallback 
 *          to parent element if the font is missing.
 * Updated: 09 July 2009 10:52pm
 * 
 */

/**
 * Actual function that does all the work. Returns an array with all the info.
 * This test will fail for the font set as the default serif font.
 * 
 * Usage: d = new Detector();
 *        d.test('font_name');
 */
var Detector = function(){
        var h = document.getElementsByTagName("BODY")[0];
        var d = document.createElement("DIV");
        var s = document.createElement("SPAN");
        d.appendChild(s);
        d.style.fontFamily = "sans";                        //font for the parent element DIV.
        s.style.fontFamily = "sans";                        //serif font used as a comparator.
        s.style.fontSize   = "72px";                        //we test using 72px font size, we may use any size. I guess larger the better.
        s.innerHTML        = "mmmmmmmmmmlil";                //we use m or w because these two characters take up the maximum width. And we use a L so that the same matching fonts can get separated
        h.appendChild(d);
        var defaultWidth   = s.offsetWidth;                //now we have the defaultWidth
        var defaultHeight  = s.offsetHeight;        //and the defaultHeight, we compare other fonts with these.
        h.removeChild(d);
        /* test
         * params:
         * font - name of the font you wish to detect
         * return: 
         * f[0] - Input font name.
         * f[1] - Computed width.
         * f[2] - Computed height.
         * f[3] - Detected? (true/false).
         */
        function debug(font) {
                h.appendChild(d);
                var f = [];
                f[0] = s.style.fontFamily = font;        // Name of the font
                f[1] = s.offsetWidth;                                // Width
                f[2] = s.offsetHeight;                                // Height
                h.removeChild(d);
                font = font.toLowerCase();
                if (font == "serif") {
                        f[3] = true;        // to set arial and sans-serif true
                } else {
                        f[3] = (f[1] != defaultWidth || f[2] != defaultHeight);        // Detected?
                }
                return f;
        }
        function test(font){
                f = debug(font);
                return f[3];
        }
        this.detailedTest = debug;
        this.test = test;        
}