<pre class="javascript" name="code">	

	var fm = document.getElementsByTagName('form')[0];

	var button = document.getElementsByName("button");

	//获取一个cookie的值	function getCookie(index){		var allcookies = document.cookie;  		var cookie_pos = allcookies.indexOf(index);		if (cookie_pos != -1){			cookie_pos += index.length + 1;			var cookie_end = allcookies.indexOf(";",cookie_pos); 			if (cookie_end == -1){    				cookie_end = allcookies.length;  			}  			var value = http://www.mamicode.com/unescape(allcookies.substring(cookie_pos, cookie_end)); >
	//获取文本光标位置并设置一个cookie来存储光标时时变动的位置的函数	var textpos = 0;	textcontent.onclick  = function(){		textpos = getCursortPosition (textcontent);		document.cookie="textpos="+textpos;				textpos = getCookie("textpos");	}	//字符串的写入函数	function content(string){			s = textcontent.value;		fm.content.value  = http://www.mamicode.com/s.substring(0,getCookie("textpos"))+string+s.substring(getCookie("textpos"));>
<pre class="php" name="code">	//点击按钮向表单中的文本域的光标处添加内容	button[0].onclick  = function(){		content('[b][/b]');	}