Javascript for number only

function CheckDateEntry(e)
{

var e = event || evt;
var keyval = e.which || e.keyCode;

alert(keyval);
if((keyval>=48 && keyval <=57) || (keyval==111 || keyval==191 || keyval==8 || keyval==46 || keyval==37 || keyval==39 || keyval==35 || keyval==36 || keyval==47))
{
return true;
}
else
{
return false;
}
}