纯js实现的论坛常用的运行代码的效果

<div style="margin-top: 1em; margin-bottom: 1em"><div style="display:none">{1}</div><textarea rows="12" cols="95" style='font-family:"Courier New",Courier,monospace;'></textarea><script src="runcode.js"></script><br /><input type="button" value="运行代码" style="border-left:1px solid #B1B4CD;border-right:1px solid #494D74;border-top:1px solid #B1B4CD;;border-bottom:1px solid #494D74;background:#696D81;color:#FFFFFF;" onclick="runCode(this)"> <input type="button" style="border-left:1px solid #B1B4CD;border-right:1px solid #494D74;border-top:1px solid #B1B4CD;;border-bottom:1px solid #494D74;background:#696D81;color:#FFFFFF;"value="复制代码" onclick="copycode(this)"> <input type="button" style="border-left:1px solid #B1B4CD;border-right:1px solid #494D74;border-top:1px solid #B1B4CD;;border-bottom:1px solid #494D74;background:#696D81;color:#FFFFFF;"value="另存代码" onclick="saveCode(this)"> <input type="button" style="border-left:1px solid #B1B4CD;border-right:1px solid #494D74;border-top:1px solid #B1B4CD;;border-bottom:1px solid #494D74;background:#696D81;color:#FFFFFF;"value="还原代码" onclick="preCode(this)">  提示：您可以先修改部分代码再运行</div>

//Scripts runcode for BBS ver 2008-06-30, by Bound0(bound0@veryhman.com) 
//First published at http://bbs.blueidea.com 
//An example: http://bbs.veryhman.com/showtopic-20094.aspx 

function runCode(which) { 
    var p=which.parentNode; 
    var os=p.getElementsByTagName("textarea"); 
    if(os.length==0)return; 
    var o=os[0]; 
        var winname = window.open('', "_blank", ''); 
        winname.document.open('text/html', 'replace'); 
        winname.opener = null; 
        winname.document.write(o.value); 
        winname.document.close(); 
} 
function saveCode(which) { 
    var p=which.parentNode; 
    var os=p.getElementsByTagName("textarea"); 
    if(os.length==0)return; 
    var o=os[0]; 
        var winname = window.open('', '_blank', 'top=10000'); 
        winname.document.open('text/html', 'replace'); 
        winname.document.write(o.value); 
        winname.document.execCommand('saveas','','code.htm'); 
        winname.close(); 
} 
function copycode(which) { 
    var p=which.parentNode; 
    var os=p.getElementsByTagName("textarea"); 
    if(os.length==0)return; 
    var o=os[0]; 
    var is_ie = (userAgent.indexOf('msie') != -1 && !is_opera) && userAgent.substr(userAgent.indexOf('msie') + 5, 3); 
    if(is_ie && o.style.display != 'none') { 
        var rng = document.body.createTextRange(); 
        rng.moveToElementText(o); 
        rng.scrollIntoView(); 
        rng.select(); 
        rng.execCommand("Copy"); 
        rng.collapse(false); 
    } 
} 
function text(e) 
{ 
    var t = ""; 
    e = e.childNodes || e; 
    for ( var j = 0; j < e.length; j++ ) 
    { 

        if(e[j].nodeType != 1){t+=e[j].nodeValue} 
        else 
        { 
            var k=e[j].nodeName; 
            if(k=='BR'||k=='P'){t+='\r\n'} 
            t+=text(e[j].childNodes) 
        } 
    } 
    return t; 
} 
function preCode(which) { 
    var p=which.parentNode; 
    var os=p.getElementsByTagName("textarea"); 
    if(os.length==0)return; 
    var o=os[0]; 
    var osv=p.getElementsByTagName("div"); 
    if(osv.length==0)return; 
    var ov=osv[0]; 
    var c='' 
    if(typeof(ov.innerText)!="undefined"){c=ov.innerText}else{c=text(ov)} 
    o.value=c 
} 
(function(){var s=document.getElementsByTagName("script");preCode(s[s.length-1])})()