var isNS4 = (navigator.appName==”Netscape”)?1:0;
function checkCharacter(event){
if(!isNS4){
if(event.keyCode == 8 || event.keyCode == 0 ) return true;
if(event.keyCode < 46 || event.keyCode > 57 ) {
event.returnValue = false;
}
}
else{
if(event.which == 8 || event.which == 0 ) return true;
if(event.which < 46 || event.which > 57 ) {
return false;
}
}
}
</> MV Techbytes 
Reblogged this on Zeeshan Akhter.