changed existing selected_values check to use value instead of value/label

I don't see a reason to use the label instead of the value:

    selected_values.push($(this).val() + "-" + $(this).text());

Why not just use:

    selected_values.push($(this).val())

I was having trouble with returned JSON and encoded HTML entities not matching the label that was pulled from the page using `.text()` - sure it is possible to also use `.html()` but why not forget about the labels and check for duplicates / existing based on the selected value and not the label? the part of the code that was changed is not used when displaying the dropdown, etc.