jquery1.3源码中有趣的链接--globalEval

http://webreflection.blogspot.com/2007/08/global-scope-evaluation-and-dom.html这篇文章很有意思。

   这种创建script标签并且设置script.text以动态执行JavaScript代码的方法，在IE下与eval和window.execScript的性能差不多，但是在firefox3下性能比eval平均高2.4倍。

// Evalulates a script in a global context
globalEval: function( data ) {
	if ( data && /\S/.test(data) ) {
		// Inspired by code by Andrea Giammarchi
		// http://webreflection.blogspot.com/2007/08/global-scope-evaluation-and-dom.html
		var head = document.getElementsByTagName("head")[0] || document.documentElement,
			script = document.createElement("script");

		script.type = "text/javascript";
		if ( jQuery.support.scriptEval )
			script.appendChild( document.createTextNode( data ) );
		else
			script.text = data;

		// Use insertBefore instead of appendChild  to circumvent an IE6 bug.
		// This arises when a base node is used (#2709).
		head.insertBefore( script, head.firstChild );
		head.removeChild( script );
	}
},