function trim(t) {
		s=t
	  while (s.substring(0,1) == ' ') {
		s = s.substring(1,s.length);
	  }
	  while (s.substring(s.length-1,s.length) == ' ') {
		s = s.substring(0,s.length-1);
	  }
	  return s;
	}
	
	function email(frm,c){
		function request_email(){
			if (http.readyState==4){
	  			if (http.status==200){
					if (parseInt(http.responseText)>0){
						alert ('Este correo electrónico ya está registrado, introduce otro');
						frm.cEmail.value = "";						
						frm.cEmail.focus();
						}												
					}
	  			else{
					alert("ERROR DE VALIDACIÓN: " + http.statusText)
					}					
				}		
			}
	
		http=new ActiveXObject("Microsoft.XMLHTTP");
		if ((http)&&(frm.cEmail.value!=''))
		{					
			http.onreadystatechange=request_email;
			url = '/kxrvuelta/library/email.Request.asp?c=' + trim(c);
			http.open("GET",url,true);
			http.send();
		}
		
			
	}