var whitespace = " \t\n\r";
// Check whether string s is empty.
function isEmpty(s)
{ return ((s == null) || (s.length == 0)) }

function isWhitespace (s)
{
var i;
// 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 ForceEntry(val, str) {
var strInput = new String(val.value);

if (isWhitespace(strInput)) {
alert(str);
return false;
} else
return true;

}