// Check whether string s is empty.

function isEmpty(s)
{   return ((s == null) || (s.length == 0))

}


// Returns true if string s is empty or 
// whitespace characters only.


function isWhitespace (s)
{   var i;
    var whitespace = " \t\r\n";
    // Is s empty?
    if (isEmpty(s)) return true;
    // Search through string's characters one by one
    // until we find a non-whitespace character.
    // When we do, return false; if we don't, return true.

    for (i = 0; i < s.length; i++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);

        if (whitespace.indexOf(c) == -1) return false;
    }

    // All characters are whitespace.
    return true;
}


function solo_caracter(field){
	var ok = "yes";
 var valid = "abcdefghijklmnñopqrstuvwxyz ABCDEFGHIJKLMNÑOPQRSTUVWXYZáéíóúÁÉÍÓÚ";
     for (var i=0; i<field.value.length; i++) {
       temp = "" + field.value.substring(i, i+1);
       if (valid.indexOf(temp) == "-1") ok = "no";
    }
     if (ok == "no") {
        alert("Caracter(es) invalido(s) Solo se permiten letras");
        field.value="";
        field.focus();
        field.select();

 }
}

function solo_numeros(field){
      var valid = "0123456789- ";
      var ok = "yes";
      var temp;
      for (var i=0; i<field.value.length; i++) {
        temp = "" + field.value.substring(i, i+1);
        if (valid.indexOf(temp) == "-1") ok = "no";
      }
      if (ok == "no") {
         alert("Caracter(es) invalido(s) Solo se permiten numeros");
         field.value="";
         field.focus();
         field.select();
                 return false;
      }
          return true;
}