控制字数的textbox

效果:http://www.haoyouxian.com/message.asp

html

<!--显示字数的textarea-->

<span><a href="javascript:void();" style="color:#0000FF" id="phote"  >加入表情</a></span><br />

<textarea id="cContent" name="cContent" rows="10" wrap=PHYSICAL cols="50" onKeyDown="gbcount(this.form.cContent,this.form.total,this.form.used,this.form.remain);" onKeyUp="gbcount(this.form.cContent,this.form.total,this.form.used,this.form.remain);"></textarea>

 &nbsp;<span id="content" style="color:#FF0000">*</span>&nbsp; 

<p>最多字数： 

<input disabled maxLength="4"  name="total" size="3" value="200" class="inputtext"> 

已用字数： 

<input disabled maxLength="4" name="used" size="3" value="0" class="inputtext"> 

剩余字数： 

<input disabled maxLength="4" name="remain" size="3" value="200" class="inputtext"> 

</p>

js

//gaonan
//导航用的
function checktext(text) 
{ 
allValid = true; 
for (i = 0; i < text.length; i++) 
{ 
if (text.charAt(i) != " ") 
{ 
allValid = false; 
break; 
} 
} 
return allValid; 
} 

function gbcount(message,total,used,remain) 
{ 
var max; 
max = total.value; 
if (message.value.length > max) { 
message.value = message.value.substring(0,max); 
used.value = max; 
remain.value = 0; 
alert("留言不能超过 200 个字!"); 
} 
else { 
used.value = message.value.length; 
remain.value = max - used.value; 
} 
}