jQuery - getting custom attribute from selected option

That because the element is the "Select" and not "Option" in which you have the custom tag.

Try this: $("#location option:selected").attr("myTag").

Hope this helps.

Suppose you have many selects. This can do it:

$('.selectClass').change(function(){
    var optionSelected = $(this).find('option:selected').attr('optionAtribute');
    alert(optionSelected);//this will show the value of the atribute of that option.
});

Try this:

$(function() { 
    $("#location").change(function(){ 
        var element = $(this).find('option:selected'); 
        var myTag = element.attr("myTag"); 

        $('#setMyTag').val(myTag); 
    }); 
}); 

You're adding the event handler to the <select> element.
Therefore, $(this) will be the dropdown itself, not the selected <option>.

You need to find the selected <option>, like this:

var option = $('option:selected', this).attr('mytag');