[jQuery] $.post() can't work in IE7, but work in IE8

Hey All,

I wrote code below:

$('a[rel*=showapformdata]').click(function(){
        $.post("ajax/ajaxapform.php",{op: "personalData", id: $
(this).attr("title")},
            function(data){
            $("#resultbox").hide();
            $("#apformbox #tab1").html(data);
            $("#apformbox").fadeIn(400);
            },"html");
    return false;
});

when I click the button, #apformbox doesn't show anything in IE7, but
work fine in IE8/FF/Chrome;
Can anyone see what I'm doing wrong?

sorry for my poor english.