1

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  
 2     <html xmlns="http://www.w3.org/1999/xhtml">  
 3     <head>  
 4     <meta http-equiv="Content-Type" content="text/html; charset=GBK" />  
 5     <title>js获取光标位置</title>  
 6     <script type="text/javascript">
 7     /** 
 8     * 获取光标所在的字符位置 
 9     * @param obj 要处理的控件, 支持文本域和输入框 
10     * @author hotleave 
11     */  
12     function getPosition(obj){  
13     //alert(obj.tagName);  
14     var result = 0;  
15     if(obj.selectionStart){ //非IE浏览器  
16        result = obj.selectionStart  
17     }else{ //IE  
18        var rng;  
19        if(obj.tagName == "TEXTAREA"){ //如果是文本域  
20         rng = event.srcElement.createTextRange();  
21         rng.moveToPoint(event.x,event.y);  
22        }else{ //输入框  
23         rng = document.selection.createRange();  
24        }  
25        rng.moveStart("character",-event.srcElement.value.length);  
26        result = rng.text.length;  
27     }  
28     return result;  
29     }  
30       
31     function getValue(obj){  
32          var pos = getPosition(obj);  
33     //alert(pos);  
34     alert(obj.value.substr(0,pos)+" [这里是添加的内容] "+obj.value.substr(pos,obj.value.length));  
35     }  
36     </script>
37     </head>  
38     <body>  
39     <input type="text" value="你好,Amethyst!" onmouseup="getValue(this)" style="display:block" mce_style="display:block">  
40     <textarea rows="6" cols="60" onmouseup="getValue(this)">Amethyst, 你好.