方法一：
function check(){
var obj = document.getElementById("num1");
var str = obj.value;
var flag=false;
for (var chr in str)
{
if(str.charAt(chr)<‘0′ || str.charAt(chr)>’9’){
flag = true;
break;
}else{
flag = false;
}
}
if(flag){
document.getElementById("mess").style.visibility ="visible";
}else{
document.getElementById("mess").style.visibility="hidden";
}
}
方法二：
function chkReg(){
var obj = document.getElementById("num1");
var str = obj.value;
var flag=false;
var reg = new RegExp(" [0-9]{1,10} ");
if(!reg.test(str)){
document.getElementById("mess").style.visibility ="visible";
}else{
document.getElementById("mess").style.visibility="hidden";
}
}调用代码
<div id="lay" class="pageWidth">
<table align="center">
<tr>
<td colspan="3" class="fot">计算器</td>
</tr>
<tr height="5px"><td colspan="3"></td></tr>
<tr>
<td>第一个数</td>
<td><input type="text" id="num1" onblur="check()"/></td>
<td><font color="red" style="visibility:hidden" id="mess">*文本框填写内容不正确</font></td>
</tr>
<tr height="5px"><td colspan="3"></td></tr>
<tr>
<td>运算符</td>
<td><select id="op">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select></td>
<td></td>
</tr>
<tr height="5px"><td colspan="3"></td></tr>
<tr>
<td>第二个数</td>
<td><input type="text" id="num2"/></td>
<td></td>
</tr>
<tr height="5px"><td colspan="3"></td></tr>
<tr>
<td><input type="button" value="结果" onclick="calc()"/></td>
<td colspan="2" id="result">0</td>
</tr>
</table>
</div>
找一个让心里安静和干净的地方，自己变得跟水晶一般透明，
