云在天边看世界

<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>
 <form>
<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>textCounter(document.getElementById("maxcharfield"),"progressbar1",120)</script>
 </form></font>