Updating list of <select> options using jquery and ajax

You can use $.getJSON if your expecting a json response. You might also be able to use $.each() and then simply .append() to the select tag. You can reference this.property inside the .each().

Something like the following:

$.getJSON("updateTypes.php?q="+brandName, function(data) {
    $("#Type").html('');
    $.each(data, function(){
        $("#Type").append('<option value="'+ this.value +'">'+ this.name +'</option>')
    )
})

This would assume your json response is something like the following:

[ { name : "foo", value : "bar" }, { name : "another", value : "example" } ]

Your code $("#Type").remove(); removes the select object not its options. The correct way of removing options is:

$("#Type option").remove();

or

$("#Type").html('');

The second solution seems to be better as stated here: How to remove options from select element without memory leak?

There is also an error in the part that adds new options. Your javascript code should be:

var brandName = $("#Brand").val();

$.get("updateTypes.php?q="+brandName, function(data) {

    $("#Type option").remove();
    var typeData = JSON.parse(data);

    for (loop=0; loop < typeData.length; loop++) {
        $("#Type").get(0).options.add(new Option(typeData[loop]));
    }
});

The $('#Type').get(0) method refers to the raw DOM object which has the "options" property that you wanted to use (How to get a DOM Element from a JQuery Selector)