"http://www.w3.org/tr/html4/loose.dtd">
Whether is a number title>
hEAD>
Function isnum (O)
{
Var pattern = / ^ / d * $ /;
// Description: 2 / is the grammar of the positive value, / d is any number, is equivalent to [0-9], ^ means to begin with the number, $ indicates to end with the number. Chen Dehui
IF (! Pattern.Test (O.Value))
{alert ("must be a number!"); o.value = "";
}
script>