Question

im making a wordpress plugin and i have a function where i import images, this is done with a $.each()-loop that calls a .load()-function every iteration. The load-function page the load-function calls is downloading the image and returns a number. The number is imported into a span-element. The source and destination Arrays is being imported from LI-elemnts of a hidden ULs.

this way the user sees a counter counting from zero up to the total number of images being imported. You can se my jQuery code below:

jQuery(document).ready(function($) {

    $('#mrc_imp_img').click(function(){
    var dstA = [];
    var srcA = [];
    $("#mrc_dst li").each(function() { dstA.push($(this).text()) });
    $("#mrc_src li").each(function() { srcA.push($(this).text()) });

        $.each(srcA, function (i,v) {
            $('#mrc_imgimport span.fc').load('/wp-content/plugins/myplugin/imp.php?num='+i+'&dst='+dstA[i]+'&src='+srcA[i]);
        });

    });


});

This works pretty good but sometimes it looks like the load function isn’t updating the DOM as fast as it should because sometimes the numbers that the span is updated with is lower than the previous and almost everytime a lower number is replacing the last number in the end. How can i prevent this from happening and how can i make it hide ‘#mrc_imp_img’ when the $.each-loop is ready?

Answer 1

AJAX calls which have been called earlier are not guaranteed to finish earlier so the smaller number can overwrite the bigger. One solution is to simply increment the counter on each successful call:

jQuery(function($) {
  $('#mrc_imp_img').click(function(){
    var dstList = $("#mrc_dst li");
    var srcList = $("#mrc_src li");
    dstList.each(function(i) { 
      var dst = $(this).text();
      var src = srcList[i].text();
      $.post('/wp-content/plugins/myplugin/imp.php?num='+i+'&dst='+dst+'&src='+src, function() {
        $('#mrc_imgimport span.fc').text($('#mrc_imgimport span.fc').text()+1);
      });
    });
  });
});

(Changed the code to avoid unnecessary array operations, changed onready call to use shorthand, changed AJAX call to use POST which should be used for operations that change state.)