How to execute jQuery callback before data?

Question

I have a simple post, which executed the data returned as a script as such:

$.post("/home", { foo: 'bar' }, function(){
    //callback function
}, "script");

Here's what happens:

1. The request gets sent
2. A piece of JS code is returned as a response and executed
3. The callback is executed

I need the callback to be executed before the returned JS is executed. Is there a way to achieve this?

Thanks!

Answer 1

This $.post() function does not automatically execute the JS which is returned. It is probably executed in the callback function.

Answer 2

Hello,

You could use "BeforeSend" option that is executed before send the ajax request:

$.ajax({

    type: "POST",

    url: "SOMEURL",

    data: { "WHATEVER": whatever },

    beforeSend: function() {

      //DO WHATEVER BEFORE SEND AJAX CALL

    }
.....

});

}

Hope this helps.

best regards.

Jose

Answer 3

You can't change how JQuery handle the request. After all, a callback is a callback and it gets executed once the job is done! You can, however, set the dataType to "text" and then eval your Javascript.

Ex:

$.post("/home", { foo: 'bar' }, function(data){
   //callback function

   // execute JS
   $.globalEval( data );
}, "text");

** UPDATE **

This is what JQuery does internally (snipped) :

// If the type is "script", eval it in global context
} else if ( type === "script" || !type && ct.indexOf("javascript") >= 0 ) {
   jQuery.globalEval( data );
}

So, there is no security risk with taking the globalEval out of the Ajax request and executing it in the callback function.

Answer 4

Use $.ajax() and build your own script tag.

$.ajax({url:"/home",
        data: { foo: 'bar' },
        type: "POST",
        dataType: 'text',     // Return dataType is "text" instead of "script"
        success: function( script ){
           // run your code
           alert('mycode');
           // then create your own script tag
           var tag = document.createElement('script');
           tag.setAttribute('type','text/javascript');
           tag.appendChild(document.createTextNode(script));
           document.getElementsByTagName('head')[0].appendChild(tag);
        }
});