function isEMailAddr(elem) {
	var str = elem.value;
    var re = /^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/;
    if (!str.match(re)) {
        return false;
    } else {
        return true;
    }
  }

function valida(){
	// Variables locales	
	var i,v, ko;
	ko = 0;
	
	// comprobar que los campos no esten
	var inputs = document.getElementsByTagName('input');
	for( var j = 0; j < inputs.length-1; j++ ) {
	  if(inputs[j]){
 				i=inputs[j].name+"obl";
 				if (inputs[j].value.length<=0){
 						v="visible";
 						ko++;
 				}else				v="hidden"; 						
 				document.getElementById(i).style.visibility=v;
 		} 
	}
	if (document.getElementById('cp')){
			var cp = parseInt(document.getElementById('cp').value);
			if (isNaN(cp)){
				ko++;
				document.getElementById('codigoobl').style.visibility="visible";
			}				
	}
	
	if(!isEMailAddr(document.getElementById('email'))) {
	
	ko++;
   			document.getElementById('emailobl').style.visibility="visible";
   	 	}   		
 	
	
	if(ko>0)	return false; 	
 	else		return true;

}