sorry u copy this one

function checkAddress(sText)
{
var ok = "0123456789";
var f=true;
var Char;
var text=sText.value;
for (i = 0; i {
Char=text.charAt(i);
if(ok.indexOf(Char) == -1)
{
f = false;
}

}
if (f==false)
{
alert("user enters only numbers");
}
}