JavaScript实现提示文本框还可以输入字符数的方法-优快云博客

<html>
<head>
<title>enter</title>
<script language="javascript">
function keypress1()
{
   var text1=document.getElementById("mytext1").value;
   var len=15-text1.length;
   var show="你还可以输入"+len+"个字";
   document.getElementById("name").innerText=show;
}
function keypress2()
{
   var text1=document.getElementById("myarea").value;
   var len;//记录剩余字符串的长度
   if(text1.length>=30)
   {
    document.getElementById("myarea").value=text1.substr(0,30);
    len=0;
   }
   else
   {
     len=30-text1.length;
   }
   var show="你还可以输入"+len+"个字";
   document.getElementById("pinglun").innerText=show;
}

</script>
</head>
<body>
<center>
<div style="text-align:left;">
<h>昵称:</h>
<input type="text" id="mytext1" maxlength=15 onKeyUp="keypress1()"/>
<font color="gray"><label id="name">你还可以输入15个字</label></font>
<br>
<h>评论内容:</h><br>
<textarea id="myarea" style="height:100px;width:200px;overflow-x:hidden;overflow-y:hidden" cols="10"   rows="3" onKeyUp="keypress2()" onblur="keypress2()"></textarea>
<font color="gray"><label id="pinglun">你还可以输入30个字</label></font>
<div>
</center>


</body>
</html>