Question

I found a little javascript snippet for including javascripts only if they was not included before.

That is working with my own scripts, but with two third-party libraries it’s not working and I really don’t know why.

    var included_files = new Array();
    function include_once(script_filename) {
        if (!in_array(script_filename, included_files)) {
            included_files[included_files.length] = script_filename;
            include_dom(script_filename);
        }
    }
    function in_array(needle, haystack) {
        for (var i = 0; i < haystack.length; i++) {
            if (haystack[i] == needle) {
                return true;
            }
        }
        return false;
    }
    function include_dom(script_filename) {
        var html_doc = document.getElementsByTagName('head').item(0);
        var js = document.createElement('script');
        js.setAttribute('language', 'javascript');
        js.setAttribute('type', 'text/javascript');
        js.setAttribute('src', script_filename);
        html_doc.appendChild(js);
        return false;
    }

function loaded() {
    include_once("shared/scripts/jquery.min.js");
    include_once("shared/scripts/iscroll.js");

    $(document).ready(function () {
        alert("hello");
    });
}

error: $ is not defined.
If I import jQuery the regular way its working and it says “iScroll” is not defined (because I’m using it later).

Any ideas?

Answer 1

Did someone say callback?

function include_once(script_filename, callback) {
        if (!in_array(script_filename, included_files)) {
            included_files[included_files.length] = script_filename;
            include_dom(script_filename, callback);
        }
    }

function include_dom(script_filename, callback) {
    var html_doc = document.getElementsByTagName('head').item(0);
    var js = document.createElement('script');
    js.setAttribute('language', 'javascript');
    js.setAttribute('type', 'text/javascript');
    js.setAttribute('src', script_filename);
    if(callback && callback != 'undefined'){
        js.onload =  callback;
        js.onreadystatechange = function() {
            if (this.readyState == 'complete') callback();
        }
    }
    html_doc.appendChild(js);
    return false;
}

function loaded() {
    include_once("shared/scripts/jquery.min.js", function(){
        $(document).ready(function () {
            alert("hello");
        });
    });
    include_once("shared/scripts/iscroll.js");
}