用javascript限制一个文本框只能输入数字

<input   name=mlizhong   size=4   value=''   maxlength=4    
      onkeypress="return   event.keyCode>=48&&event.keyCode<=57"    
      onpaste="var   s=clipboardData.getData('text');   if(!/\D/.test(s))   value=s.replace(/^0*/,'');   return   false;"   ondragenter="return   false"    
      style="ime-mode:disabled"     onkeyup="if(/(^0+)/.test(value))value=value.replace(/^0*/,   '')">

javascript限制輸入數字,兼容IE,Firefox javascript

2008/05/21 15:28

<SCRIPT>
<!--
        var isIE = false;
        var isFF = false;

        if ((navigator.userAgent.indexOf("MSIE")>0) && (parseInt(navigator.appVersion) >=4)) isIE = true;
        if (navigator.userAgent.indexOf("Firefox")>0) isFF = true;

        function isNUM(e)
        {
            var iKeyCode = window.event?e.keyCode:e.which;
            if(!(((iKeyCode >= 48) && (iKeyCode <= 57)) || (iKeyCode == 13) || (iKeyCode == 46) || (iKeyCode == 45) || (iKeyCode == 37) || (iKeyCode == 39) || (iKeyCode == 8)))
            {  
                if (isIE)
                {
                    e.returnValue=false;
                }
                else
                {
                    e.preventDefault();   //重要 firefox是用prevenDefault()来取消事件的
                }
            }
        }  
//-->
</SCRIPT>
<input type="text" onkeypress="return isNUM(event)">

當然在判斷鍵盤輸入中加入正則表達式,會靈活很多.