function includes(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;
	  }
}