Question

In my php file I have two select menus. When the first one is selected second one gets the values with jquery. It works fine in simple php file. But when pasted to a file with JQuery mobile a little problem occurs:
With changing the first one, values of the second one changes fine but the first one’s selected option still remains.

Here is my .js file:

function deg(){
var id = document.getElementById("il").options[document.getElementById("il").selectedIndex].value;
var ilcx;

switch(id){
case "a":
ilcx = {"x" : "x"
}; break;
case "b":
ilcx = {"y" : "y"
}; break;
case "c":
ilcx = {"c" : "c"
}; break;

}

var $el = $("#ilcx");
$el.empty(); 
$.each(ilcx, function(key, value) {
  $el.append($("<option></option>")
     .attr("value", value).text(key));
});

and php’s part:

 <select name="il" id="il" onchange="deg();">
                            <option id="a" value="a">a</option>
                            <option id="b" value="b">b</option>
                            <option id="c" value="c">c</option>
  </select>
                        <select name="ilcx" id="ilcx">
                            <option id="x" value="x">x</option>
                            <option id="y" value="y">y</option>
                            <option id="z" value="z">z</option>

    </select>

Answer 1

Made a jsfiddle with the solution

HTML

<select name="il" id="il">
    <option id="a" value="x" selected="selected">a</option>
    <option id="b" value="y">b</option>
    <option id="c" value="c">c</option>
</select>
<select name="ilcx" id="ilcx">
    <option id="x" value="x" selected="selected">x</option>
    <option id="y" value="y">y</option>
    <option id="z" value="z">z</option>
</select>

JS

$(document).on('change', '#il', function() { deg(this); });

function deg(obj){
    var val = obj.value,
        $el = $('#ilcx'),
        $opt = $('<option />');

    $opt.val(val).text(val).appendTo($el);
}