JavaScript
Article

Simulating Delay using jQuery and setTimeout()

By Sam Deering

Sometimes you may wish to simulate a delay of events such as simulating loading of results before showing on the page. This example uses a recursive setTimeout() to call a function which loops through an array of data which has the results of a system precheck to check for things such as JavaScript, Flash, Browser Version etc… When I get time I might code this into a jQuery plugin which will be easy just need to determine which options to provide to cater for different usage.

simulating-delay-in-jquery

Demo

jQuery Code Recursive setTimeout()

//data and settings
var result = ‘

Precheck passed.

‘, //html for main result
delay = 500, //delay of sub results
data = Array(

  • Javascript
  • ‘,

  • System
  • ‘,

  • Device
  • ‘,

  • Browser
  • ‘,

  • Flash

  • );

    //self executing function starting from array index 0
    (function process_els(el_index) {

    var el = data[el_index],
    precheckUl = $(‘#precheck ul’),
    loadingLi = $(‘

  • ‘),
    sysPreId = “syspre_”+el_index;

    //show loading image
    precheckUl.append(loadingLi.clone().attr(“id”,sysPreId));

    //after simulated delay replace loading image with sub check result
    setTimeout( function()
    {
    precheckUl.find(‘li.loading:first’).replaceWith(data[el_index]);

    }, delay);

    //to simulate the delay recursively call itself until all array elements have been processed
    if (el_index + 1 < data.length) { setTimeout(function() { process_els(el_index + 1); }, delay); } else { setTimeout(function() { //append the final result after all sub checks have been inserted precheckUl.after(result); }, (delay*2)); } })(0); [/js]

    ​HTML

    System Check

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