Ajax，防止点击多个请求

Question

I'm trying to prevent multiple requests when user click on login or register button. This is my code, but it doesn't work. Just the first time works fine, then return false..

$('#do-login').click(function(e) {
    e.preventDefault();

    if ( $(this).data('requestRunning') ) {
        return;
    }

    $(this).data('requestRunning', true);

    $.ajax({
        type: "POST",
        url: "/php/auth/login.php",
        data: $("#login-form").serialize(),
        success: function(msg) {
            //stuffs
        },
        complete: function() {
            $(this).data('requestRunning', false);
        }
    });      
}); 

Any ideas? Thanks!

Answer 1

The problem is here:

    complete: function() {
        $(this).data('requestRunning', false);
    }

this no longer points to the button.

$('#do-login').click(function(e) {
    var me = $(this);
    e.preventDefault();

    if ( me.data('requestRunning') ) {
        return;
    }

    me.data('requestRunning', true);

    $.ajax({
        type: "POST",
        url: "/php/auth/login.php",
        data: $("#login-form").serialize(),
        success: function(msg) {
            //stuffs
        },
        complete: function() {
            me.data('requestRunning', false);
        }
    });      
}); 

Answer 2

Use on() and off() , that's what they are there for :

$('#do-login').on('click', login);

function login(e) {
    e.preventDefault();
    var that = $(this);
    that.off('click'); // remove handler
    $.ajax({
        type: "POST",
        url: "/php/auth/login.php",
        data: $("#login-form").serialize()
    }).done(function(msg) {
        // do stuff
    }).always(function() {
        that.on('click', login); // add handler back after ajax
    });
}); 

Answer 3

您可以禁用该按钮。

$(this).prop('disabled', true);

Answer 4

In your ajax callbacks the context ( this ) changes from the outer function, you can set it to be the same by using the context property in $.ajax

$.ajax({
    type: "POST",
    url: "/php/auth/login.php",
    data: $("#login-form").serialize(),
    context: this, //<-----
    success: function(msg) {
        //stuffs
    },
    complete: function() {
        $(this).data('requestRunning', false);
    }
});      

Answer 5

I have also faced a similar problem.

Just adding $('#do-login').attr("disabled", true); gives me the solution.

$('#do-login').click(function(e) {
   e.preventDefault();
   $('#do-login').attr("disabled", true);
   .........
   .........

Here do-login is button id.

Answer 6

I've tried this and worked very fine for me, I was having trouble that $.ajax send more request until results return,

 var settings = {
    "url": "/php/auth/login.php",
    "method": "POST",
    "timeout": 0,
    "async": false,
    "headers": {
        "Content-Type": "application/json; charset=utf-8"
    },
    "data": jsondata, //data pass here is in JSON format
};
$.ajax(settings).done(function (ress) {
  try{
      console.log(ress, "Result from Ajax here");
    }
    catch(error){
      alert(error);
      console.log(ress);
    }
});

async : false worked for me. Thanks.

Answer 7

Or you can do it by $(this).addClass("disabled"); to you button or link and after click is performed, you can $(this).removeClass("disabled"); .

// CSS

.disabled{
cursor: not-allowed;

}

// JQUERY

$('#do-login').click(function(e) {
   e.preventDefault();

    $(this).addClass("disabled");
    $.ajax({
        type: "POST",
        url: "/php/auth/login.php",
        data: $("#login-form").serialize(),
        context: this,
        success: function(msg) {
    //do more here

           $(this).removeClass("disabled");
        },
    });
});

PS If you use bootstrap css, you do not need the css part.

Answer 8

I found the approach useful. I've implemented it as a general purpose function for jQuery with ES6.

export default function (button, promise) {
    const $button = $(button);
    const semaphore = 'requestRunning';

    if ($button.data(semaphore)) return null;
    $button.data(semaphore, true);

    return promise().always(() => {
        $button.data(semaphore, false);
    });
}

Because $.ajax() returns a promise, you simply pass in the promise and the function takes care of the rest.

Roughly speaking, here's the usage.

import preventDoubleClick from './preventdoubleclick';

...

button.click(() => {
    preventDoubleClick(this, () => $.ajax()
        .done(() => { console.log("success") }));
});

Answer 9

This function can help you with control multi Ajax requests and it's has timeout function which can return flag status to 0 after ex. 10sec (In case the server took more than 10 seconds to respond)

var Request_Controller = function(Request_Name = '', Reactivate_Timeout = 10000)
{
    var a = this;
    a.Start_Request = function(){
        if(window.Requests == undefined){
            window.Requests = {};
        }
        window.Requests[Request_Name] = {'Status' : 1, 'Time': + new Date()};
    }

    a.End_Request = function(){
        if(window.Requests == undefined){
            window.Requests = [];
        }
        window.Requests[Request_Name] = undefined;
    }

    a.Is_Request_Running = function(){
        if(window.Requests == undefined || window.Requests[Request_Name] == undefined){
            return 0;
        }else{
            var Time = + new Date();
            // Reactivate the request flag if server take more than 10 sec to respond
            if(window.Requests[Request_Name]['Time'] < (Time - Reactivate_Timeout)) 
            {
                return 0;
            }else{
                return 1
            }
        }
    }
}

To use it:

var Request_Flag = new Request_Controller('Your_Request_Name');
if(!Request_Flag.Is_Request_Running()){

    Request_Flag.Start_Request();

    $.ajax({
        type: "POST",
        url: "/php/auth/login.php",
        data: $("#login-form").serialize(),
        success: function(msg) {
            //stuffs
        },
        complete: function() {
            Request_Flag.End_Request();
        }
    }); 
}

Answer 10

for prevent multiple ajax request in whole site. For example: If use ajax request in other ajax page, Using ajax in php loop, etc, Give you multiple ajax request with one result. I have solution:

Use window.onload = function() { ...  } 

instead of

$(document).ready(function(){ ...  });

on the main index.php page. Its will be prevent all multi request. :)