[html] Correct way to use Modernizr to detect IE?

I agree we should test for capabilities, but it's hard to find a simple answer to "what capabilities are supported by 'modern browsers' but not 'old browsers'?"

So I fired up a bunch of browsers and inspected Modernizer directly. I added a few capabilities I definitely require, and then I added "inputtypes.color" because that seems to cover all the major browsers I care about: Chrome, Firefox, Opera, Edge...and NOT IE11. Now I can gently suggest the user would be better off with Chrome/Opera/Firefox/Edge.

This is what I use - you can edit the list of things to test for your particular case. Returns false if any of the capabilities are missing.

/**
 * Check browser capabilities.
 */
public CheckBrowser(): boolean
{
    let tests = ["csstransforms3d", "canvas", "flexbox", "webgl", "inputtypes.color"];

    // Lets see what each browser can do and compare...
    //console.log("Modernizr", Modernizr);

    for (let i = 0; i < tests.length; i++)
    {
        // if you don't test for nested properties then you can just use
        // "if (!Modernizr[tests[i]])" instead
        if (!ObjectUtils.GetProperty(Modernizr, tests[i]))
        {
            console.error("Browser Capability missing: " + tests[i]);
            return false;
        }
    }

    return true;
}

And here is that GetProperty method which is needed for "inputtypes.color".

/**
 * Get a property value from the target object specified by name.
 * 
 * The property name may be a nested property, e.g. "Contact.Address.Code".
 * 
 * Returns undefined if a property is undefined (an existing property could be null).
 * If the property exists and has the value undefined then good luck with that.
 */
public static GetProperty(target: any, propertyName: string): any
{
    if (!(target && propertyName))
    {
        return undefined;
    }

    var o = target;

    propertyName = propertyName.replace(/\[(\w+)\]/g, ".$1");
    propertyName = propertyName.replace(/^\./, "");

    var a = propertyName.split(".");

    while (a.length)
    {
        var n = a.shift();

        if (n in o)
        {
            o = o[n];

            if (o == null)
            {
                return undefined;
            }
        }
        else
        {
            return undefined;
        }
    }

    return o;
}