Drop the javascript into the console and call the function on the element you are interested in, like so:
var dimensions = getResponsiveDimensions($('.my-object'));
Then resize the browser window, crazily, or slowly, however you please, until you are satisfied. The data you want will be in dimensions
.
dimensions.minWidth, dimensions.maxWidth, dimensions.minHeight, dimensions.maxHeight
You will see the min and max width and height of the element. The accuracy of these numbers depends on how thorough your screen resizing was.
dimensions.missing
A list of window pixel widths not collected. A length of zero guarantees your dimensions are accurate.
dimensions.list
An object with window width as key and dimensions of element in question at that window width.