How to Show Progress Bar While Loading, Using Ajax

AJAX progress bar of load script

Writing and reading session doesn't work because the standard behavior of PHP is to lock the session file while your main code is being executed.

Try to create a file and update the its content with the percentage done during the execution of your function. Something like:

<?php
function slowFunction() {
    $file = uniqid();
    file_put_contents($file, 0);
    // Long while that makes your stuff
    // you have to know how many loops you will make to calculate the progress
    $total = 100;
    $done = 0;
    while($done < $total) {
        $done++;
        // You may want not to write to the file every time to minimize changes of being writing the file 
        // at the same time your ajax page is fetching it, i'll let it to you...
        $progress = $done / $total;
        file_put_contents($file, $progress);
    }
    unlink($file); // Remove your progress file
}

How to delay Ajax and show progress bar while loading

Use the ajax start/stop handlers:

var loading = $('.loader').hide();
$(document)
  .ajaxStart(function() {
    loading.show();
  })
  .ajaxStop(function() {
    loading.hide();
  });

HTML:

 <div class="loader" style="display:none;"></div>

CSS:

.loader {
    border: 16px solid #f3f3f3; /* Light grey */
    border-top: 16px solid #3498db; /* Blue */
    border-radius: 50%;
    width: 120px;
    height: 120px;
    animation: spin 2s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

show progressbar while loading pages using jquery ajax in single page website

Allow me to refer you to this page , it desribes how you can add a progress event listener to the xhr object (which only works in these browsers, in older browsers you simply have rely on the same base you're currently using) in jquery.

For reference I have copied the relevant code below (you would only be interested in the 'Download progress' part probably):

$.ajax({
  xhr: function()
  {
    var xhr = new window.XMLHttpRequest();
    //Upload progress
    xhr.upload.addEventListener("progress", function(evt){
      if (evt.lengthComputable) {
        var percentComplete = evt.loaded / evt.total;
        //Do something with upload progress
        console.log(percentComplete);
      }
    }, false);
    //Download progress
    xhr.addEventListener("progress", function(evt){
      if (evt.lengthComputable) {
        var percentComplete = evt.loaded / evt.total;
        //Do something with download progress
        console.log(percentComplete);
      }
    }, false);
    return xhr;
  },
  type: 'POST',
  url: "/",
  data: {},
  success: function(data){
    //Do something success-ish
  }
});

Do allow me to say though that this is a lot of overkill for a single page website and only really becomes useful for large files. Additionally images and similar media aren't handled in this way and you would need to monitor the loading of images (or do it yourself through ajax) to make such a system perfect.

Here is a JSFiddle showing this in action: http://jsfiddle.net/vg389mnv/1/

Progress bar is not showing immediately during ajax call

try this

function submit() {
  jQuery("#myProgressBar").show();
  doAjaxCall(aftersuccess);
}

function doAjaxCall(callback) {
  var ajaxResult = null;
  jQuery.ajax({
    url: someUrl,
    data: someData,

    success: function(result) {
     callback(result);
    }


  });
return result;
}

function  aftersuccess(data){
 jQuery("#myProgressBar").hide();
alert(data);
}

update progress bar using ajax request seconds

I think this post is quite clear
http://www.dave-bond.com/blog/2010/01/JQuery-ajax-progress-HMTL5/

Posting this for future reference (should the blog be removed):

$.ajax({
     xhr: function(){
       var xhr = new window.XMLHttpRequest();
       //Upload progress
       xhr.upload.addEventListener("progress", function(evt){
       if (evt.lengthComputable) {
         var percentComplete = evt.loaded / evt.total;
         //Do something with upload progress
         console.log(percentComplete);
         }
       }, false);
     //Download progress
       xhr.addEventListener("progress", function(evt){
         if (evt.lengthComputable) {
           var percentComplete = evt.loaded / evt.total;
         //Do something with download progress
           console.log(percentComplete);
         }
       }, false);
       return xhr;
     },
     type: 'POST',
     url: "/",
     data: {},
     success: function(data){
    //Do something success-ish
    }
 });