Question

I am working on MVC appliction .I have a masterpage which is calling external javascript file and sometimes child page also calling the javascript file. i want if one time it is added by child page or masterpage it should not again add that Javascript file. please help me this i have done but is not working
enter code here

    $(document).ready(function () {
        var fileref1 = document.createElement('script')
        fileref1.type = "text/javascript";
        fileref1.src = "~/Scripts/testZoomPlugin.js";
        fileref1.Id = "testZoomJS";
        if (typeof fileref1 == "undefined") {
            $.getScript('~/Scripts/testZoomPlugin.js');
        }
        fileref1.src = "~/Scripts/jquery.ui.widget.min.js";
        fileref1.Id = "testWidget";

        if (typeof fileref1 == "undefined") {
            $.getScript('~/Scripts/jquery.ui.widget.min.js');
        }
        fileref1.src = "~/Scripts/jquery.ui.slider.min.js";
        fileref1.Id = "testSlider";
        if (typeof fileref1 == "undefined"){
            $.getScript('~/Scripts/jquery.ui.slider.min.js');
        }
        if(typeof fileref1=="undefined"){
            $.getScript('~/Scripts/jquery.ui.slider.min.js');
    });

Answer 1

Just use RequireJS, it does what you need and have a straight-forward syntax, in your case it will be something like this :

<script src="~/Scripts/require.js"></script>
<script>
var modules = [], prefix = "~/Scripts/";
modules.push( prefix + "testZoomPlugin.js" );
modules.push( prefix + "jquery.ui.widget.min.js" );
    require( modules, function( someModule ) {
        //This function will be called when all the dependencies
        //listed above are loaded. Note that this function could
        //be called before the page is loaded.
        //This callback is optional.
    });
</script>