How can I minimize the repetition of code with this jquery ajax?

I have many functions on a page, where the following code is exactly the same, except for the data being sent, and the success div to display the result to. For example:

One ajax post:

$.ajax({
    type: 'POST',
    url: 'unique_file.php',
    data: {qty: 2, item_id: 13},
    cache: false,
    success: function(data) {
       $('#return_div').html(data);
    }
});  

Another ajax post:

$.ajax({
    type: 'POST',
    url: 'another_unique_file.php',
    data: {no_shipping: 4},
    cache: false,
    success: function(data) {
      $('#a_differen开发者_如何学Got_div').html(data);
    }
});

So I was thinking it would be ideal to make this into a function like so

function do_ajax(post_file,results_div,post_data) {
$.ajax({
    type: 'POST',
    url: post_file,
    data: {post_data}, // this doesn't appear to work
    cache: false,
    success: function(data) {
      $(results_div).html(data);
    }
});
}

Then I can achieve #1 ajax like so:

do_ajax('unique_file.php','#return_div','qty: 2, item_id: 13');

This seems logical to me, but the limits of my logic are how to get the data into my function. Perhaps the post_data is not just a string like that but more something like:

do_ajax('purchase_create.php','#create_purchase_window','item_id:'+$item_id+', qty: '+$qty+'');

Which looks pretty messy... but mostly, it just doesn't work. Is there a cleaner way of perhaps putting all the data into an array and giving that to the function?

You can use ajaxSetup to set defaults.

$.ajaxSetup({
  cache: false,
  type: 'POST'
});

then

$.ajax({
    url: post_file,
    data: {post_data: post_data}, // this doesn't appear to work
    success: function(data) {
      $(results_div).html(data);
    }
});

{post_data} is not correct syntax. So I changed it to {post_data: post_data}

You're on the right track:

function do_ajax(post_file,results_div,post_data) {
$.ajax({
    type: 'POST',
    url: post_file,
    data: post_data,
    cache: false,
    success: function(data) {
      $(results_div).html(data);
    }
});
}

do_ajax('purchase_create.php, '#create_purchase_window', {
    item_id: 3,
    qty: 2
});

You're passing an object to POST, so just pass that object into your do_ajax function and pass it along.