求一个复杂的正则表达式！

后台获取得字符串：
<p><img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /> 1111 <img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /></p>要转换成<p><img style="float:none;margin:0px;" alt="" src="htt://feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /> 1111 <img style="float:none;margin:0px;" alt="" src="htt://feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /></p>要找出原字符串中的所有img标签的src属性例如：feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png,拼接成http://feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png替换原来的src属性！难！！！

解决方案 »

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http://feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png这个url 也不对啊               <script>
               var s='<p><img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /> 1111 <img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /></p>';
               alert(s.replace(/<img (.*?)src="(.+?)"(.*?)>/,'<img $1src="http://$2"$3>'));
               </script>
这个url是不对的只是举个例子的
你写的那段js不能运行啊
var s='';
s= s.replace(/src="([^"]+)"/gi, 'src="http://$1"');
<html>
<head>
<script>
function rp(){
var h = document.getElementById("test").innerHTML;
alert(h.replace(/<img(.*?)src="[^http:\/\/](.+?)"(.*?)>/g,'<img$1src="http://$2"$3>'));}
</script></head>
<body>
<div id="test">
<p><img style="float:none;margin:0px;" alt="" src="http://feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /> 1111 <img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /></p>
</div>
<input type="button" value="替换" onclick="rp()"/>
</body>
</html>
  <html>
<head>
    <title>无标题页</title>
    <script type="text/javascript" src="js/jquery-1.7.1.min.js"></script>
    <script type="text/javascript">
        $(document).ready(function() {
            var s = '<p><img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /> 1111 <img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /></p>';
            $("#btn").click(function() {
                var patt = new RegExp(/<img[\s|\S|\s]*?src=[\s|\"|\']*([^>\"\']*)[\s|\S]*?>/ig);
                while ((result = patt.exec(s)) != null) {
                    s = s.replace(result[1], "http://"+result[1]);
                }
                alert(s);
            });
        });
    </script>
</head>
<body>
  <input type="button" id="btn" onclick="test()" value="测试" />
</body>
</html>
刚弄错了  这个是对的你可以测试下直接复制运行<html>
<head>
<script>
function gg(){
var s="<img src='feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png' />";
s= s.replace(/src=(')/gi, 'src=$1http://');
alert(s);
}
</script>
</head>
<body>
<a href="#" onclick="gg();">替换</a>
</body>
</html>
再发一次 <html>
<head>
<script>
function gg(){
var s="<img src='feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png' />";
s= s.replace(/src=(')/g, 'src=$1http://');
alert(s);
}
</script>
</head>
<body>
<a href="#" onclick="gg();">替换</a>
</body>
</html>
发错了上面的代码  这个才OK的
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>无标题页</title>
    <script type="text/javascript">
        function test() {
            var s = '<p><img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /> 1111 <img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /></p>';
            var patt = new RegExp(/<img[\s|\S|\s]*?src=[\s|\"|\']*([^>\"\']*)[\s|\S]*?>/ig);
            while ((result = patt.exec(s)) != null) {
                s = s.replace(result[1], "http://" + result[1]);
            }
            alert(s);
        }
    </script>
</head>
<body>
  <input type="text" id="txtVal" /> <input type="button" id="btn" onclick="test()" value="测试" />
</body>
</html>
我那个没问题 src 如果用单引号括起来就用 s= s.replace(/src=(')/g, 'src=$1http://'); 如果是双引号括起来就用s= s.replace(/src=(")/g, 'src=$1http://');
  <script>
  var s='<p><img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /> 1111 <img style="float:none;margin:0px;" alt="" src="feedAttachment/attachment/19/1324343834390/feed_img_pview_500_400.png" /></p>';
  alert(s.replace(/<img (.*?)src="(.+?)"(.*?)>/ig,'<img $1src="http://$2"$3>'));
  </script> 之前随手写的，没考虑大小写和多匹配g （全文查找出现的所有 pattern）
i （忽略大小写）
m （多行查找）