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*$/g, "";
}
function F(objid{
return document.getElementById(objid.value;
}
function G(objid{
return document.getElementById(objid;
}
</script>
</head>
<body onLoad="keyUp(;">
<div>
<table width="100%" border="0" cellspacing="0" cellpadding="0" style="position:relative">
<tr>
<td width="55%">
<div id="ol"><textarea cols="2" rows="10" id="li" disabled></textarea></div>
<textarea name="co" cols="60" rows="10" wrap="off" id="c2" onblur="check('2'" onKeyUp="keyUp(" onFocus="clearValue('2'" onscroll="G('li'.scrollTop=this.scrollTop;" oncontextmenu="return false" class="grey">请在这里粘入多段字看一看。
</textarea>
</td>
</tr>
</table>
</div>
<em class="block" id="msg2">文本框没有内容。</em>
<script type="text/javascript">
var msgA=["msg1","msg2","msg3","msg4"];
var c=["c1","c2","c3","c4"];
var slen=[50,20000,20000,60];//允许最大字数
var num="";//https://www.feishuai.vip/javascript-function/752.html
var isfirst=[0,0,0,0,0,0];
function isEmpty(strVal{
if( strVal==""
return true;
else
return false;
}
function isBlank(testVal{
var regVal=/^\s*$/;
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>