// A utility function that returns true if a string contains only
// whitespace characters.
function isblank(s)
{
    for(var i = 0; i < s.length; i++) {
        var c = s.charAt(i);
        if ((c != ' ') && (c != '\n') && (c != '\t')) return false;
    }
    return true;
}
// This is the function that performs form verification. It will be invoked
// from the onSubmit() event handler. The handler should return whatever
// value this function returns.
function verify(f)
{
    var msg;
    var empty_fields = "";
    var errors = "";
		var last_element_name = "";

    // Loop through the elements of the form, looking for all
    // text and textarea elements that don't have an "optional" property
    // defined. Then, check for fields that are empty and make a list of them.
    // Also, if any of these elements have a "min" or a "max" property defined,
    // then verify that they are numbers and that they are in the right range.
    // Put together error messages for fields that are wrong.
    for(var i = 0; i < f.length; i++) {
        var e = f.elements[i];

		// Si dos elementos del formulario tienen el mismo nombre se 
		// mira el primero y el resto se saltan
      	if (e.name != last_element_name)
      		last_element_name = e.name;
      	else
     		continue;

        // cogemos el nombre quitandole el _value
        if (e.desc!=null ) nombre=e.desc;
        else nombre=e.name;

        if (((e.type == "text") || (e.type == "textarea") || (e.type == "password") || (e.type == "file")) && !e.optional) {
            // first check if the field is empty
            if ((e.value == null) || (e.value == "") || isblank(e.value)) {
                empty_fields += "\n          " + nombre;
                continue;
            }
            // Now check for fields that are supposed to be numeric.
            if (e.numeric || (e.min != null) || (e.max != null)) {
                var v = parseFloat(e.value);
                if (isNaN(v) ||
                    ((e.min != null) && (v < e.min)) ||
                    ((e.max != null) && (v > e.max))) {
                    errors += "- El campo " + nombre + " debe ser un numero";
                    if (e.min != null)
                        errors += " mayor que " + e.min;
                    if (e.max != null && e.min != null)
                        errors += " y menor que " + e.max;
                    else if (e.max != null)
                        errors += " menor que " + e.max;
                    errors += ".\n";
                }
            }
        }

        if ((e.type == "radio")&&!e.optional){
        		if (!radioChecker(e.name)&& empty_fields.indexOf(e.name)==-1 ) empty_fields += "\n          " + nombre;
    		}
      	else if ( typeof e.multiple != 'undefined' && ( e.multiple || !e.multiple ) &&!e.optional ){
        		if ( e.selectedIndex<1 && empty_fields.indexOf(e.name)==-1 ) empty_fields += "\n          " + nombre;
    		}

    }


    // Now, if there were any errors, then display the messages, and
    // return false to prevent the form from being submitted. Otherwise
    // return true.
    if (!empty_fields && !errors) return true;
    msg  = "______________________________________________________\n\n"
    msg += "El formulario no ha sido enviado debido a los siguientes errores.\n";
    msg += "Por favor , corrijalos y vuelva a enviarlo.\n";
    msg += "______________________________________________________\n\n"
    if (empty_fields) {
        msg += "- Los siguientes campos requeridos están vacíos:"
                + empty_fields + "\n";
        if (errors) msg += "\n";
    }
    msg += errors;
    alert(msg);
    return false;
}


function radioChecker(nombre) {
	valores=eval('document.forms[1].'+nombre);
	 for (i=0;i<valores.length;i++){
	   	  if (valores[i].checked==true) return true;
	 }
	return false;
}