if($('#tt2').length>0){ 

<!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></title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <!--   引入jQuery -->
    <script src="../../scripts/jquery.js" type="text/javascript"></script>
</head>
<body>
    <div id="tt">test</div>
    <div id="tt2">test2</div>
    <div id="tt3">test3</div>
    <script type="text/javascript">
        $('#tt').css("color","red");
        if($('#tt2').length>0){
            $('#tt3').html('yes #tt2');
        }else{
            $('#tt3').html('no #tt2');
        }

        if($('#tt4').length>0){
            $('#tt').html('yes #tt4');
        }else{
            $('#tt').html('no #tt4');
        }

    </script>
</body>
</html>

 

posted @ 2017-10-17 16:59  sky20080101  阅读(48)  评论(0)    收藏  举报