限制textarea的输入字数

来源：互联网发布：郭麒麟知乎编辑：程序博客网时间：2024/04/30 02:22

<!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>网页特效限制textarea的输入字数 </title>
<script type="text/javascript">
function checkLength(){
    var curLength = $("www_zzjs_net").value.length;
    //alert("已经输入的字数：" + curLength );
    if (curLength>150){
        alert("超过字数限制，多出的字将被截断！" );
        $("www_zzjs_net").value = $("www_zzjs_net").value.substr(0,150);
        curLength = 150;
    }
$("count_zzjs").innerHTML = 150-$("www_zzjs_net").value.length;
}
function $(id){
return document.getElementById(id);
}
window.onload = function(){
if(/msie/i.test(navigator.userAgent)){
$("www_zzjs_net").onpropertychange = checkLength;
} else {
$("www_zzjs_net").addEventListener("input",checkLength,false);
}
}
</script>
</head>
<body>

<label>
提示您：还可以输入<span id="count_zzjs">150</span>字<br>
<textarea name="textarea" id="www_zzjs_net" cols="45" rows="5">
</textarea>
</label>
</body>
</html>