javascript 字数实时检测

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>无标题页</title>
    <script type="text/javascript">
       function checkLength(which) 
       {  
            var maxChars = 250;  
          
            if (which.value.length > maxChars)  
                which.value = which.value.substring(0,maxChars);  
          
            var curr = maxChars - which.value.length;  
              
            document.getElementById("chLeft").innerHTML = curr.toString();  
        }  
    </script> 
</head>
<body style="font-size:12px;">
    <textarea name="description" onkeyup="checkLength(this);" style="width: 312px; height: 121px"></textarea>   
    <br />
    <span>文字最大长度: 250. 还剩: <span id="chLeft">250</span>.</span>
    </body>
</html>
posted @ 2008-04-09 16:45  chy710  阅读(120)  评论(0)    收藏  举报