function numbersonly( e )
{
var unicode = e.charCode ? e.charCode : e.keyCode;

//if the key isn't the backspace key (which we should allow)
if( unicode != 8 )
{ 
//if not a number
if( unicode < 48 || unicode > 57 )
{
//disable key press
return false;
}//end if
else
{
// enable keypress
return true;
}//end else
}//end if
else
{
// enable keypress
return true;
}//end else
}//end function