javascript让文本框只能输入数字, 带数字类型和限制最大值功能.

网上看到过很多javascript验证数字输入的方法, 自己也写了个算是总结吧. 如有算法和逻辑上的问题, 欢迎大家拍砖啊.
IE6.0下测试通过.

转载请注明出自: http://blog.csdn.net/pisces_fri/

<SCRIPT language="javascript" type="text/javascript">
/**
* @author: pisces.fri
*/

// =============================================================================
// validationNumber methods

/**
* Validate the input text as a number
*
* @param object ID of the input control object
* @param string Number type ('int', 'u_int', 'float' or 'u_float')
* @param number Max number allowed to input
* @param object ID of the error message control object
*
* @return null
*/
function validationNumber(hndID, numType, maxNum, hndMsgID)
{
var keyCode = window.event.keyCode;
var ch = String.fromCharCode(keyCode);
var value = '';
var retCode = 0;
var oNumVerify=null;

//屏蔽回车键
if (keyCode==13)
{
window.event.keyCode = 0;
return null;
}

if (hndID != undefined)
{
value += hndID.value+ch;
}
else
{
window.event.keyCode = keyCode;
return null;
}

oNumVerify = new isNumeric(value);
if (oNumVerify.isNumber)
{
numType = numType.toString().toLowerCase();
switch(numType)
{
case 'u_int': //正整数
if ((oNumVerify.isMinus==false) && (oNumVerify.isDecimal==false))
{
retCode = keyCode;
}
break;
case 'u_float': //正实数
if (oNumVerify.isMinus==false)
{
retCode = keyCode;
}
break;
case 'int': //整数
if (oNumVerify.isDecimal==false)
{
retCode = keyCode;
}
break;
case 'float': //实数
retCode = keyCode;
break;
default:
retCode = 0;
}

//判断输入的数字是否超过设置的最大值
if ((maxNum!=undefined) && (maxNum.constructor==Number) && (oNumVerify.value > maxNum))
{
retCode = 0;
if (hndMsgID != undefined)
{
hndMsgID.innerHTML = '<SPAN style="color:#EE3333">值不能大于'+maxNum+'</SPAN>';
}
}
}

oNumVerify = null;
window.event.keyCode = retCode;
return null;
}

function isNumeric(verifyNum)
{
var re = /^([-]{0,1})([0-9]*)([/.]{0,1})([0-9]*)$/g;
this.isNumber = false;
this.isMinus = false;
this.isDecimal = false;
this.value = verifyNum;

verifyNum = verifyNum.toString();

if (re.test(verifyNum))
{
this.isNumber = true;
re.exec(verifyNum);

//判断 '-' 符号
if (RegExp.$1=='-')
{
this.isMinus = true;
}

//判断 '.' 符号
if (RegExp.$3=='.')
{
this.isDecimal = true;
verifyNum += '0';
}

try
{
this.value = parseFloat(verifyNum);
}
catch(e)
{
this.value = 0;
}
}

return;
}
</SCRIPT>
使用方法:<br/>
<INPUT type="text" name="txtYear" id="txt_Year" size="4" onkeypress="javascript:validationNumber(this, 'float', 2006, txtYearMsg);" style="text-align:right;ime-mode:disabled;" maxlength="4"/>年  <SPAN id="txtYearMsg"></SPAN>

IE6.0下测试通过.