可主要用于留言板等地的小部分文字书写。
代码如下：
<head id="Head1" runat="server">
<title>限制文本框输入字数</title>
<style type="text/css">
.progress
{
width: 1px;
height: 14px;
color: white;
font-size: 12px;
overflow: hidden;
background-color: navy;
padding-left: 5px;
}
</style>
<script type="text/JavaScript">
function textCounter(field,counter,maxlimit,linecounter) {
// text width//
var fieldWidth = parseInt(field.offsetWidth);
var charcnt = field.value.length;
// trim the extra text
if (charcnt > maxlimit) {
field.value = field.value.substring(0, maxlimit);
}
else {
// progress bar percentage
var percentage = parseInt(100 - (( maxlimit - charcnt) * 100)/maxlimit) ;
document.getElementById(counter).style.width = parseInt((fieldWidth*percentage)/100)+"px";
document.getElementById(counter).innerHTML="已输: "+percentage+"%"
// color correction on style from CCFFF -> CC0000
setcolor(document.getElementById(counter),percentage,"background-color");
}
}
function setcolor(obj,percentage,prop){
obj.style[prop] = "rgb(80%,"+(100-percentage)+"%,"+(100-percentage)+"%)";
}
</script>
<p>
限制：120字节</p>
</head>
<body>
<form id="form1" runat="server">
<textarea rows="5" cols="40" name="maxcharfield" id="maxcharfield" onkeydown="textCounter(this,'progressbar1',120)"
onkeyup="textCounter(this,'progressbar1',120)" onpaste="textCounter(this,'progressbar1',120)"
onfocus="textCounter(this,'progressbar1',120)"></textarea><br />
<div id="progressbar1" class="progress">
</div>
<script type="text/jscript">textCounter(document.getElementById("maxcharfield"),"progressbar1",120)</script>
</form>
</body>
以前用的，感觉不错……
转载于:https://www.cnblogs.com/aizhan/archive/2013/01/22/IceBirds.html