jquery - jquery.post 不工作

Question

当我在本地计算机上尝试此代码时，它运行良好并放回我需要的数据，但是当我将它放在网站服务器上时，它没有通过...检查兼容性加载它在 .post 方法处停止

<script src="http://code.jquery.com/jquery-1.9.1.min.js" type="text/javascript"></script>
<!-- <script src="js/settings.js" type="text/javascript"></script>-->
<SCRIPT type="text/javascript">
    pic1 = new Image(16, 16);
    pic1.src = "loader.gif";

    $(document).ready(function() {

        $("#username").change(function() {

            var usr = $("#username").val();

            if (usr.length >= 3) {

                $.post("check.php", {
                    username: "donald"
                },

                function(data, status) {
                    alert("Data: " + data + "\nStatus: " + status);
                });

                $("#status").html('<img src="loader.gif" align="absmiddle">&nbsp;Checking availability...');

                $.ajax({
                    type: "POST",
                    url: "check.php",
                    data: "username=" + usr,

                    error: function() {
                        aler('error');
                    },
                    success: function(msg) {

                        $("#status").ajaxComplete(function(event, request, settings) {

                            if (msg == 'OK') {

                                $("#username").removeClass('object_error'); // if necessary
                                $("#username").addClass("object_ok");
                                $(this).html('&nbsp;<img src="accepted.png" align="absmiddle"> <font color="Green"> Available </font>  ');
                            } else {
                                $("#username").removeClass('object_ok'); // if necessary
                                $("#username").addClass("object_error");
                                $(this).html(msg);
                            }

                        });

                    }

                });

            } else {
                $("#status").html('<font color="red">The username should have at least    
    <strong>3</strong> characters.</font>');
                $("#username").removeClass('object_ok'); // if necessary
                $("#username").addClass("object_error");
            }

        });

    });

    //-->
</SCRIPT>
<style type="text/css">
    body {
        font-family:"Trebuchet MS";
        font-size:12px;
    }
    .inn {
        float:left;
        font-size:14px;
        border:solid 1px #000000;
        width:143px;
        font-family:Arial, Helvetica, sans-serif;
        color:#0066CC;
        font-weight:bold;
    }
</style>
<table>
    <tr>
        <td width="35%" align="right" valign="middle" id="abc">User Name :</td>
        <td width="65%" align="left" valign="middle">
            <input id="username" type="text" name="username" class="inn" />&nbsp; http://xyz.com/<span id="username_url" style="color:#006600; font-weight:bold;">USERNAME</span> 
        </td>
    </tr>
    <tr>
        <td></td>
        <td align="left" valign="bottom" height="20px">
            <div id="status"></div>
        </td>
    </tr>
</table>