AJAX邮寄表格无效。 它绝对无能为力

Question

There was an error in my code and there was also a js file included inside my page which prevented anything from executing inside $(document).ready(function () { ...

i'm trying to sumbit this login form:

<form class="form" id="AjaxForm">
        <input type="text" name="username" placeholder="Username">
        <input type="password" name="password" placeholder="Password">
        <button type="submit" id="login-button">Login</button>
</form>

Via ajax with this code:

var request;
$("#AjaxForm").submit(function(event){

    // Abort any pending request
    if (request) {
        request.abort();
    }
    // setup some local variables
    var $form = $(this);

    // Let's select and cache all the fields
    var $inputs = $form.find("input, select, button, textarea");

    // Serialize the data in the form
    var serializedData = $form.serialize();

    // Let's disable the inputs for the duration of the Ajax request.
    // Note: we disable elements AFTER the form data has been serialized.
    // Disabled form elements will not be serialized.
    $inputs.prop("disabled", true);

    // Fire off the request to /form.php
    request = $.ajax({
        url: "login.php",
        type: "post",
        data: serializedData
    });

    // Callback handler that will be called on success
    request.done(function (response, textStatus, jqXHR){
        // Log a message to the console
        console.log("Hooray, it worked!");
    });

    // Callback handler that will be called on failure
    request.fail(function (jqXHR, textStatus, errorThrown){
        // Log the error to the console
        console.error(
            "The following error occurred: "+
            textStatus, errorThrown
        );
    });

    // Callback handler that will be called regardless
    // if the request failed or succeeded
    request.always(function () {
        // Reenable the inputs
        $inputs.prop("disabled", false);
    });

    // Prevent default posting of form
    event.preventDefault();
  });

Which i found here: jQuery Ajax POST example with PHP

I'm trying to post it to login.php which checks if it is a valid username and password. But when i press the Login button it just puts the username and the password in the url and does nothing. And when i add action="login.php" method="POST" It submits the form but not via ajax because when i comment the ajax code out it still submits. I'm trying to prevent that. Any insights on my problem?

EDIT: lives here for now: http://5f6738d9.ngrok.io/test/public/index.html username and password are test

Answer 1

Your submit button is a standard submit type button which means that your form will be submitted normally. Based on your HTML code it will just submit the form to the same URL. The JS code will not have time to execute. All you need to do is cancel de default HTML form submit by adding

event.preventDefault();

You need to add this first thing in your submit listener. So your JS code will start like this

$("#AjaxForm").submit(function(event){
    event.preventDefault();
    // Abort any pending request
    if (request) {
        request.abort();
    }
    //....

Try using the following code:

$(document).ready(function(){
    $('#AjaxForm').on('submit', function(event){
        event.preventDefault();

        if(request){
            request.abort();
            request = false;
        }

        var $form = $(this);
        var serializedData = $form.serialize();
        var $inputs = $form.find("input, select, button, textarea");
        $inputs.prop("disabled", true);

        var request = $.ajax({
            url: 'login.php',
            type: 'POST',
            data: serializedData,
            success: function (data, textStatus, jqXHR) {
                // login was successful so maybe refresh the page
                window.location.reload();
            },
            error: function (jqXHR, textStatus, errorThrown) {
                // display form errors received from server
            },
            complete: function (jqXHR, textStatus) {
                request = false;
            }
        });
    });
});

Answer 2

Check that the event is bound within a $(document).on('ready' ... otherwise the event won't fire and the form will just submit normally or not via AJAX.

Your code should look like:

$(document).on('ready', function () {
    var request;
    $("#AjaxForm").submit(function(event){

    // Abort any pending request
    if (request) {
        request.abort();
    }
    // setup some local variables
    var $form = $(this);

    // Let's select and cache all the fields
    var $inputs = $form.find("input, select, button, textarea");

    // Serialize the data in the form
    var serializedData = $form.serialize();

    // Let's disable the inputs for the duration of the Ajax request.
    // Note: we disable elements AFTER the form data has been serialized.
    // Disabled form elements will not be serialized.
    $inputs.prop("disabled", true);

    // Fire off the request to /form.php
    request = $.ajax({
        url: "login.php",
        type: "post",
        data: serializedData
    });

    // Callback handler that will be called on success
    request.done(function (response, textStatus, jqXHR){
        // Log a message to the console
        console.log("Hooray, it worked!");
    });

    // Callback handler that will be called on failure
    request.fail(function (jqXHR, textStatus, errorThrown){
        // Log the error to the console
        console.error(
            "The following error occurred: "+
            textStatus, errorThrown
        );
    });

    // Callback handler that will be called regardless
    // if the request failed or succeeded
    request.always(function () {
        // Reenable the inputs
        $inputs.prop("disabled", false);
    });

    // Prevent default posting of form
    event.preventDefault();
  });
});

Note that these callback events are actually deprecated as of jQuery 1.8.

You will also need to ensure that your POST and action attributes are set on the form in all cases.

Answer 3

Personally I would use this instead:

$(document).ready(function(){
    $("#AjaxForm").on("submit",function(e){
        e.preventDefault();

        var $form = $(this);
        var $cacheData = $form.find("input, submit");
        var serializedData = $form.serialize();

        $.ajax({
            url: $form.attr("action"),
            type: $form.attr("method"),
            data: serializedData,
            xhrFields: {
                onprogress: function(e){
                    $cacheData.prop("disabled", true);
                    console.log(e.loaded / e.total*100 + "%");
                }
            },
            done: function(text){
                if(text == "Succes!"){
                    alert(text);
                } else {
                    alert(text);
                }
            },
            fail: function(xhr, textStatus, errorThrown){
                alert(textStatus + " | " + errorThrown);
            },
            always: function(){
                $cacheData.prop("disabled", false);
            }
        });
    });
});

This allows you to do some usefull things:

1. You're able to monitor the progress in the console
2. Just because Ajax is succesfull, doesn't mean you can't have an error returned. For example: Wrong password. So now you can simple echo errors back this script will show them. Echo "Succes!" when the login was fine.

Keep in mind though that this script requires that you set the HTML attributes action and method in your form.