javascript Limit the input digital 限制輸入數字

//-------------------------------------------------------code---------------------------------------------------------------
<input type="text" onkeypress="javascript:KeyPress(this);">
<script>
function KeyPress(objTR)
{                         
                var txtval=objTR.value;             
                var key = event.keyCode;

                if((key < 48||key > 57)&&key != 46)
                {              
                        event.keyCode = 0;
                }
                else
                {
                        if(key == 46)
                        {
                                if(txtval.indexOf(".") != -1||txtval.length == 0)
                                        event.keyCode = 0;
                        }
                }
}
</script>
 //-------------------------------------------------------code---------------------------------------------------------------
 but  Firebox  show   mesge error
 Firefox will show "var key = event.keyCode;" error ,Change another one

但是用火狐會顯示 "var key = event.keyCode;" 這行錯誤
 所以改另用一個方法

 //-------------------------------------------------------code---------------------------------------------------------------<input type="text" onkeyup="this.value=this.value.replace(/[^0-9]/g,'')" >
  //-------------------------------------------------------code---------------------------------------------------------------
 Direct use of regularization
直接使用正規化