I'm building a jQuery plugin and I have some standard settings in my JS file. 

I want people to change those settings in my HTML file. It's only working for a small part at the moment. I can already change the settings in my HTML file, but when I leave the settings in my HTML file blank it will stay blank. 

Let's say I want an image to have a width of 100px. I type `imageWidth = "100px"` in my HTML and the `imageWidth` will actually be 100px. But when I leave `imageWidth = ;` like this the `imageWidth` will be 0 because I didn't give it a width. 

I want it so that my `imageWidth` will turn into my standard setting `imageWidth` if `imageWidth = "";`. 

Here's my JS code in the HTML:

```
$(function() {
    $(document).jqueryPlugin({
        frontImage: "",
        backImage: "",
        imageHeight: "",
        imageWidth: ""
    }, {
        dialogHeight: "",
        dialogWidth: ""
    });
});

```

And here's part of my js code:

```
(function($) {
    $.fn.jqueryPlugin = function(optionsImage, optionsDialog) {
        var imageSettings = {
            frontImage: "http://www.c-and-a.com/iview/FRONT_ZOOM2X/148243_1.jpg",
            backImage: "http://www.c-and-a.com/iview/BACK_ZOOM2X/148243_1.jpg",
            imageHeight: "400px",
            imageWidth: "auto"
        };

        optionsImage = optionsImage || imageSettings.frontImage;

        var dialogSettings = {
            dialogHeight: "auto",
            dialogWidth: "auto"
        };

        if (optionsImage) {$.extend(imageSettings, optionsImage)}
        if (optionsDialog) {$.extend(dialogSettings, optionsDialog)}

```