利用js打造的一个非常实用简易的文本编辑框，可以显示行号并且同时兼容ie和firefox等主流浏览器，如下效果图：
以下是该效果的源码：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<title>显示行号的文本框效果，兼容ie、火狐等浏览器</title>
<style type="text/css">
#main{color:#666}
textarea{border:1px solid #7f9db9;font-size:9pt;width:430px;color:#000}
.grey{color:#999}
#msg1,#msg2,#msg3,#msg4{ display:none}
#ol{position:absolute;z-index:1;padding:0px;margin:0px;border:0px;background:#ecf0f5;width:23px;text-align:left; }
#li{background:#ecf0f5;height:160px;overflow:hidden;width:32px;border-right:0;line-height:20px;margin:0px;padding:0px;text-align:center}
#c2{font-family:Arial, Helvetica, sans-serif;height:160px; margin:0px; width:416px;padding:0 0 0 35px;overflow-x: hidden;line-height:20px;}
</style>
<script type="text/javascript">
String.prototype.trim2=function(){
return this.replace(/(^\s*)|(\s*$)/g, "");
}
function F(objid){
return document.getElementById(objid).value;
}
function G(objid){
return document.getElementById(objid);
}
</script>
</head>
<body onLoad="keyUp();">
<div>
<table width="100%" border="0" cellspacing="0" cellpadding="0" style="position:relative">
<tr>
<td width="55%">
<div id="ol"><textarea cols="2" rows="10" id="li" disabled></textarea></div>
<textarea name="co" cols="60" rows="10" wrap="off" id="c2" onblur="check('2')" onKeyUp="keyUp()" onFocus="clearValue('2')" onscroll="G('li').scrollTop=this.scrollTop;" oncontextmenu="return false" class="grey">请在这里粘入多段字看一看。
</textarea>
</td>
</tr>
</table>
</div>
<em class="block" id="msg2">文本框没有内容。</em>
<script type="text/javascript">
var msgA=["msg1","msg2","msg3","msg4"];
var c=["c1","c2","c3","c4"];
var slen=[50,20000,20000,60];//允许最大字数
var num="";//http://www.maopiaopiao.com/javascript-function/752.html
var isfirst=[0,0,0,0,0,0];
function isEmpty(strVal){
if( strVal=="" )
return true;
else
return false;
}
function isBlank(testVal){
var regVal=/^\s*$/;
return (regVal.test(testVal))
}
function chLen(strVal){
strVal=strVal.trim2();
var cArr=strVal.match(/[^\x00-\xff]/ig);
return strVal.length+(cArr==null ? 0 : cArr.length);
}
function check(i){
var iValue=F("c"+i);
var iObj=G("msg"+i);
var n=(chLen(iValue)>slen[i-1]);
if((isBlank(iValue)==true)||(isEmpty(iValue)==true)||n==true){
iObj.style.display ="block";
}else{
iObj.style.display ="none";
}
}
function checkAll(){
for(var i=0;i<msgA.length;i++){
check(i+1);
if(G(msgA[i]).style.display=="none"){
continue;
}else{
alert("填写错误,请查看提示信息！");
return;
}
}
G("form1").submit();
}
function clearValue(i){
G(c[i-1]).style.color="#000";
keyUp();
if(isfirst[i]==0){
G(c[i-1]).value="";
}
isfirst[i]=1;
}
function keyUp(){
var obj=G("c2");
var str=obj.value;
str=str.replace(/\r/gi,"");
str=str.split("\n");
n=str.length;
line(n);
}
function line(n){
var lineobj=G("li");
for(var i=1;i<=n;i++){
if(document.all){
num+=i+"\r\n";
}else{
num+=i+"\n";
}
}
lineobj.value=num;
num="";
}
function autoScroll(){
var nV=0;
if(!document.all){
nV=G("c2").scrollTop;
G("li").scrollTop=nV;
setTimeout("autoScroll()",20);
}
}
if(!document.all){
window.addEventListener("load",autoScroll,false);
}
</script>
</body>
</html>