function include(file,opt){
           
            if(file=="") return;
     
            //Genera una id para el archivo con el fin de evitar que se cargue 2 veces.
            idfile = file.replace(location.hostname,"");
            idfile = idfile.replace(location.protocol,"");
            idfile = idfile.replace("//","");
     
            if(document.getElementById(idfile)){ return };
                   
            if(typeof opt=="undefined") opt = {};
            if(typeof opt.cache=="undefined") opt.cache = true;
            if(typeof opt.dom=="undefined")  opt.dom = false;
            if(typeof opt.type=="undefined")  opt.type = "";
           
           
            ext = (opt.type!="") ? opt.type : file.substring(file.lastIndexOf('.')+1);
     
            if(!opt.cache){
                var random = new Date().getTime().toString();        
                    if(file.indexOf("?")!=-1) file = file+"&"+random;
                    else file = file+"?"+random;
            }
           
            if(opt.dom){
                    var head = document.getElementsByTagName('head').item(0)       
            }
           
           
            switch(ext){
                    case "css":
                      if(!opt.dom) 
                            document.write('<link rel="stylesheet" href="'+file+'" id="'+idfile+'" type="text/css"></link>');
                      else{
                        css = document.createElement('link');
                        css.rel  = 'stylesheet';
                        css.href = file;
                            css.type = 'text/css';
                            css.id = idfile;
                            head.appendChild(css);                 
                      }                    
                    break;
                   
                    case "js":
                     if(!opt.dom){
                            document.write('<script type="text/javascript" id="'+idfile+'" src="'+file+'"></script>');
                     }
                     else{
                        script = document.createElement('script');
                        script.src = file;
                            script.type = 'text/javascript';
                            script.id = idfile;
                            head.appendChild(script);
                           
                            if(typeof opt.oncomplete!="undefined"){
                                    //Para IE
                                script.onreadystatechange = function () {if (script.readyState == 'complete') {if(typeof opt.oncomplete == "function") {eval(opt.oncomplete());}}}
                                    //Para Firefox
                                script.onload = function () {if(typeof opt.oncomplete == "function") {opt.oncomplete();}}
                            }              
                     }
     
                    break;
            }
    }