If you want to restrict your text box for accepting only numeric value then try this code

Create a script function :-


function enterAmount(eve) {

try {

var val1 = (eve.which) ? eve.which : event.keyCode
if (val1 > 31 && (val1 < 48) || (val1 > 57)) {
return false;
}
}
catch (err) {
alert(err);
}


use this code in your code behind page :-

txtPaidAmount.Attributes.Add("onKeyPress", "javascript:return enterAmount(event);");