how to do file upload using jquery serialization

So I have a form and I'm submitting the form through ajax using jquery serialization function

        serialized = $(Forms).serialize();

		$.ajax({
		
		type		: "POST",
		cache	: false,
		url		: "blah",
		data		: serialized,
		success: function(data) {

		}
		

but then what if the form has an <input type="file"> field....how do I pass the file into the form using this ajax serialization method...printing $_FILES doesn't output anything

Use FormData object.It works for any type of form

$(document).on("submit", "form", function(event)
{
    event.preventDefault();
    $.ajax({
        url: $(this).attr("action"),
        type: $(this).attr("method"),
        dataType: "JSON",
        data: new FormData(this),
        processData: false,
        contentType: false,
        success: function (data, status)
        {

        },
        error: function (xhr, desc, err)
        {
            

        }
    });        

});

A file cannot be uploaded using AJAX because you cannot access the contents of a file stored on the client computer and send it in the request using javascript. One of the techniques to achieve this is to use hidden iframes. There's a nice jquery form plugin which allows you to AJAXify your forms and it supports file uploads as well. So using this plugin your code will simply look like this:

$(function() {
    $('#ifoftheform').ajaxForm(function(result) {
        alert('the form was successfully processed');
    });
});

The plugin automatically takes care of subscribing to the submit event of the form, canceling the default submission, serializing the values, using the proper method and handle file upload fields, ...

   var form = $('#job-request-form')[0];
        var formData = new FormData(form);
        event.preventDefault();
        $.ajax({
            url: "/send_resume/", // the endpoint
            type: "POST", // http method
            processData: false,
            contentType: false,
            data: formData,

It worked for me! just set processData and contentType False.

HTML

<form name="my_form" id="my_form" accept-charset="multipart/form-data" onsubmit="return false">
    <input id="name" name="name" placeholder="Enter Name" type="text" value="">
    <textarea id="detail" name="detail" placeholder="Enter Detail"></textarea>
    <select name="gender" id="gender">
        <option value="male" selected="selected">Male</option>
        <option value="female">Female</option>
    </select>
    <input type="file" id="my_images" name="my_images" multiple="" accept="image/x-png,image/gif,image/jpeg"/>
</form>

JavaScript

var data = new FormData();

//Form data
var form_data = $('#my_form').serializeArray();
$.each(form_data, function (key, input) {
    data.append(input.name, input.value);
});

//File data
var file_data = $('input[name="my_images"]')[0].files;
for (var i = 0; i < file_data.length; i++) {
    data.append("my_images[]", file_data[i]);
}

//Custom data
data.append('key', 'value');

$.ajax({
    url: "URL",
    method: "post",
    processData: false,
    contentType: false,
    data: data,
    success: function (data) {
        //success
    },
    error: function (e) {
        //error
    }
});

PHP

<?php
    echo '<pre>';
    print_r($_POST);
    print_r($_FILES);
    echo '</pre>';
    die();
?>

You can upload files via AJAX by using the FormData method. Although IE7,8 and 9 do not support FormData functionality.

$.ajax({
	url: "ajax.php", 
	type: "POST",             
	data: new FormData('form'),
	contentType: false,       
	cache: false,             
	processData:false, 
	success: function(data) {
		$("#response").html(data);
	}
});

$(document).on('click', '#submitBtn', function(e){
e.preventDefault();
e.stopImmediatePropagation();
var form = $("#myForm").closest("form");
var formData = new FormData(form[0]);
$.ajax({
	type: "POST",
	data: formData,
	dataType: "json",
	url: form.attr('action'),
	processData: false,
	contentType: false,
	success: function(data) {
		 alert('Sucess! Form data posted with file type of input also!');
	}
)};});

By making use of new FormData() and setting processData: false, contentType:false in ajax call submission of form with file input worked for me

Using above code I am able to submit form data with file field also through Ajax

HTML5 introduces FormData class that can be used to file upload with ajax.

FormData support starts from following desktop browsers versions. IE 10+, Firefox 4.0+, Chrome 7+, Safari 5+, Opera 12+

FormData - Mozilla.org