[jQuery] "async: false is not defined" - error

[jQuery] "async: false is not defined" - error


I'm getting this error
"async: false is not defined"
with Firebug 1.05 turned on
I need to post content of the textarea (not the whole form) via Ajax,
the code follows:
---
function preview()
{
    var content = $("textarea#profile_content").val();
    var preview_text = $.ajax({
    type: "POST",
    url: "preview.php",
    data: "profile_content=" + escape(content),
    async: false
    }).responseText;
    $("div#preview_area").html(preview_text);
}
---
With Firebug turned off everything works fine.
Browser is: Firefox 2.0.0.3
JQuery is: 1.1.2
Please could you help me?
Ivan