source: tmcsimulator/trunk/webapps/common/js/fileutils.js @ 442

    // Load the dynamic json file for highways, etc.

    // Ref: https://codepen.io/KryptoniteDove/post/load-json-file-locally-using-pure-javascript

    function loadJSON(inFile, callback)

    {

        var xobj = new XMLHttpRequest();

        // Assume XML unless filename ends with .json

        if (inFile.endsWith(".json"))

        {

            xobj.overrideMimeType("application/json");

        }

        if (inFile.endsWith(".csv"))

        {

            xobj.overrideMimeType("text/csv");

        }

        xobj.open('GET', inFile, true);

        xobj.onreadystatechange = function()

        {

            if (xobj.readyState == 4 && xobj.status == "200")

            {

                callback(xobj.responseText);

            }

        };

        // We want ajax to ignore any cached responses

        xobj.setRequestHeader('If-Modified-Since', 'Sat, 01 Jan 2000 01:01:01 GMT')

        xobj.send(null);

    }