Synchronous call and conflict in JQuery ajax settings

How does JQuery ajax set synchronous calls (only one function can be triggered at the same time) to solve conflicts with layer display information? The Code is as follows:

Set the following attributes before calling

The prompt layer information is displayed.

$ ("Div1"). visibility = "visible ";

/*
Delay ajax function execution. jquery1.2.6 is used here for testing. If jquery is on ie6 without delay, the layer information on ie7 cannot be displayed.
*/
SetTimeout ("ajaxSendFun ('" + url + "')", 10 );

$. AjaxSettings. async = false;

Function ajaxSendFun (url ){
$. Post (url, {}, handleResultResp, "html ");
}