请核对一下。它是完整的Ajax请求代码。

$('#foo').submit(function(event) {
    // Get the form data
    // There are many ways to get this data using jQuery (you
    // can use the class or id also)
    var formData = $('#foo').serialize();
    var url = 'URL of the request';

    // Process the form.
    $.ajax({
        type        : 'POST',   // Define the type of HTTP verb we want to use
        url         : 'url/',   // The URL where we want to POST
        data        : formData, // Our data object
        dataType    : 'json',   // What type of data do we expect back.
        beforeSend : function() {

            // This will run before sending an Ajax request.
            // Do whatever activity you want, like show loaded.
        },
        success:function(response){
            var obj = eval(response);
            if(obj)
            {
                if(obj.error==0){
                    alert('success');
                }
                else{
                    alert('error');
                }
            }
        },
        complete : function() {
            // This will run after sending an Ajax complete
        },
        error:function (xhr, ajaxOptions, thrownError){
            alert('error occured');
            // If any error occurs in request
        }
    });

    // Stop the form from submitting the normal way
    // and refreshing the page
    event.preventDefault();
});

我想分享一个详细的方法，如何张贴与PHP + Ajax以及错误抛出返回失败。

首先，创建两个文件，例如form.php和process.php。

我们将首先创建一个表单，然后使用jQuery .ajax()方法提交。其余的将在评论中解释。

form.php

<form method="post" name="postForm">
    <ul>
        <li>
            <label>Name</label>
            <input type="text" name="name" id="name" placeholder="Bruce Wayne">
            <span class="throw_error"></span>
            <span id="success"></span>
       </li>
   </ul>
   <input type="submit" value="Send" />
</form>

使用jQuery客户端验证表单并将数据传递给process.php。

$(document).ready(function() {
    $('form').submit(function(event) { //Trigger on form submit
        $('#name + .throw_error').empty(); //Clear the messages first
        $('#success').empty();

        //Validate fields if required using jQuery

        var postForm = { //Fetch form data
            'name'     : $('input[name=name]').val() //Store name fields value
        };

        $.ajax({ //Process the form using $.ajax()
            type      : 'POST', //Method type
            url       : 'process.php', //Your form processing file URL
            data      : postForm, //Forms name
            dataType  : 'json',
            success   : function(data) {
                            if (!data.success) { //If fails
                                if (data.errors.name) { //Returned if any error from process.php
                                    $('.throw_error').fadeIn(1000).html(data.errors.name); //Throw relevant error
                                }
                            }
                            else {
                                    $('#success').fadeIn(1000).append('<p>' + data.posted + '</p>'); //If successful, than throw a success message
                                }
                            }
        });
        event.preventDefault(); //Prevent the default submit
    });
});

现在我们来看看process.php

$errors = array(); //To store errors
$form_data = array(); //Pass back the data to `form.php`

/* Validate the form on the server side */
if (empty($_POST['name'])) { //Name cannot be empty
    $errors['name'] = 'Name cannot be blank';
}

if (!empty($errors)) { //If errors in validation
    $form_data['success'] = false;
    $form_data['errors']  = $errors;
}
else { //If not, process the form, and return true on success
    $form_data['success'] = true;
    $form_data['posted'] = 'Data Was Posted Successfully';
}

//Return the data back to form.php
echo json_encode($form_data);

项目文件可以从http://projects.decodingweb.com/simple_ajax_form.zip下载。

HTML:

    <form name="foo" action="form.php" method="POST" id="foo">
        <label for="bar">A bar</label>
        <input id="bar" class="inputs" name="bar" type="text" value="" />
        <input type="submit" value="Send" onclick="submitform(); return false;" />
    </form>

JavaScript:

   function submitform()
   {
       var inputs = document.getElementsByClassName("inputs");
       var formdata = new FormData();
       for(var i=0; i<inputs.length; i++)
       {
           formdata.append(inputs[i].name, inputs[i].value);
       }
       var xmlhttp;
       if(window.XMLHttpRequest)
       {
           xmlhttp = new XMLHttpRequest;
       }
       else
       {
           xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
       }
       xmlhttp.onreadystatechange = function()
       {
          if(xmlhttp.readyState == 4 && xmlhttp.status == 200)
          {

          }
       }
       xmlhttp.open("POST", "insert.php");
       xmlhttp.send(formdata);
   }

<script src="http://code.jquery.com/jquery-1.7.2.js"></script>
<form method="post" id="form_content" action="Javascript:void(0);">
    <button id="desc" name="desc" value="desc" style="display:none;">desc</button>
    <button id="asc" name="asc"  value="asc">asc</button>
    <input type='hidden' id='check' value=''/>
</form>

<div id="demoajax"></div>

<script>
    numbers = '';
    $('#form_content button').click(function(){
        $('#form_content button').toggle();
        numbers = this.id;
        function_two(numbers);
    });

    function function_two(numbers){
        if (numbers === '')
        {
            $('#check').val("asc");
        }
        else
        {
            $('#check').val(numbers);
        }
        //alert(sort_var);

        $.ajax({
            url: 'test.php',
            type: 'POST',
            data: $('#form_content').serialize(),
            success: function(data){
                $('#demoajax').show();
                $('#demoajax').html(data);
                }
        });

        return false;
    }
    $(document).ready(function_two());
</script>

我还有一个主意。

提供下载文件的PHP文件的URL。 然后你必须通过ajax触发相同的URL，我检查了这第二个请求只在你的第一个请求完成下载文件后才给出响应。所以你可以得到它的事件。

它正在通过ajax处理同样的第二个请求。

我使用这个简单的一行代码多年没有问题(它需要jQuery):

<script src="http://malsup.github.com/jquery.form.js"></script> 
<script type="text/javascript">
    function ap(x,y) {$("#" + y).load(x);};
    function af(x,y) {$("#" + x ).ajaxSubmit({target: '#' + y});return false;};
</script>

这里ap()表示Ajax页面，af()表示Ajax表单。在表单中，只需调用af()函数即可将表单发送到URL，并在所需的HTML元素上加载响应。

<form id="form_id">
    ...
    <input type="button" onclick="af('form_id','load_response_id')"/>
</form>
<div id="load_response_id">this is where response will be loaded</div>