获得 Javascript 版本

最近看一个人的BLOG,发现这个文章,非常不错,引入来存档

<script type="text/javascript">
		function getjsversion(){
			var n = navigator;
			var u = n.userAgent;
			var apn = n.appName;
			var v = n.appVersion;
			var ie = v.indexOf('MSIE ')
			if(ie > 0){
			   apv = parseInt(i = v.substring(ie + 5));
			   if(apv > 3) {
			       apv = parseFloat(i);
			   }
			}else{
			   apv = parseFloat(v);
			}
			var isie = (apn == 'Microsoft Internet Explorer');
			var ismac = (u.indexOf('Mac') >= 0);
			var javascriptVersion = "1.0";
			if(String && String.prototype){
			   javascriptVersion = '1.1';
			   if(javascriptVersion.match){
			       javascriptVersion = '1.2';
			       var tm = new Date;
			       if(tm.setUTCDate){
			           javascriptVersion = '1.3';
			           if(isie && ismac && apv >= 5) javascriptVersion = '1.4';
			           var pn = 0;
			           if(pn.toPrecision){
			               javascriptVersion = '1.5';
			               a = new Array;
			               if(a.forEach){
			                   javascriptVersion = '1.6';
			                   i = 0;
			                   o = new Object;
			                   tcf = new Function('o','var e,i=0;try{i=new Iterator(o)}catch(e){}return i');
			                   i = tcf(o);
			                   if(i && i.next) {
			                       javascriptVersion = '1.7';
			                   }
			               }
			           }
			       }
			   }
			}
			return javascriptVersion;
		}
	alert(getjsversion());
</script>

来源:http://www.phppan.com/2010/09/how-to-check-javascript-version/