grence's program note

stopWatch('test eval',[function(){
//方法一，單純 eval
	var o,s="o=({a:[1,2,3],b:4})";
	var parse =function(s){
		eval(s);
	}
	parse(s);
	return o.b;
},function(){
//方法二，new Function
	var s="o1=({a:[1,2,3],b:4})";
	window.o1;
	var parse = Function(s);
	parse(s);
	return window.o1.b;
},function(){
//方法三，呃…看起來就不會快XD
	var s="o2=({a:[1,2,3],b:4})";
	window.o2;
	var parse = function(s){
		var head = document.getElementsByTagName("head")[0] || document.documentElement,
			script = document.createElement("script");

		script.type = "text/javascript";
		script.text = s;

		head.insertBefore( script, head.firstChild );
		head.removeChild( script );
	};
	parse(s);
	return window.o2.b;
}],10000);

//測試用
function stopWatch(catgory, fn, runTimes){
	runTimes = runTimes || 100000;
	var timeSt, result=[];
	var start = function(){
		timeSt = +new Date();
	};
	var end = function(){
		return +new Date()-timeSt;
	}
	for(var f in fn){
		var testFn = fn[f];
		var testTimes = runTimes;
		var execResult;
		start();
		while(testTimes--){
			testFn();
		};
		execResult = testFn();
		var timeSpend = end();
		result.push({ fn:testFn.toString(), time:timeSpend+'ms', execResult:execResult});
	}
	//return result;

	(function renderResult(result){
		var div = document.createElement('div');
		div.className = 'test_block';
		var html = [catgory, ', 執行：', runTimes, '次'];
		html.push('<ul>');
		for(var i in result){
			var tmp = result[i]
			html.push('<li>');
			html.push('<div class="fn_content"><pre>',tmp.fn,'</pre></div>',
				'<div class="time_spend">執行時間：',tmp.time,'</div>');
			if(tmp.execResult)
				html.push('<div class="exec_result">執行結果：',tmp.execResult,'</div>');
			html.push('</li>');
		}
		html.push('</ul>');
		div.innerHTML = html.join('');
		document.body.appendChild(div);
	})(result);
}

執行結果（chrome）：

第二跟第三種函數好像只能用全域變數去接…這種 CODE我自己都不喜歡看到，速度慢，程式又醜，我想不到值得利用的場合。好吧，這種測試本來就是寫自己開心的XD，想到或看到不同的寫法，總會想試試看有沒有比較好，這樣一直累積…喜歡這種不斷改善、進步的感覺。