<script>
function validatesigns()
{
var str;
var x;
var error;
error = false;
str = document.forms.vform.vinput.value;
x = new Array('!','@','#','$','%','^','&','&','*','(',')','=','_','+');

for (i=0; i<x.length; i++)
{
if (str.indexOf(x)!=-1)
{
error = true;
}
}
if (!error)
{
document.forms.vform.submit();
}
else
{
alert(" error msg.. ");
}
}
</script>
<form name="vform">
<input name="vinput">
<input type=button onclick="validatesigns();" value="Submit form">