jQuery autocomplete: does not allow other text

I am using the below code to create auto complete extender in my grid. This is working fine. Now i need to add the listed dropdown list only otherwise the text box should be blank. Is this possible means please help me to do this.

dataInit: function (e) {
    $(e).autocomplete({
        source: ["c++", "java", "php", "coldfusion", "javascript", "asp", "ruby"],
        minLength: 1,
        focus: function (event, ui) {
            $(e).val(ui.item.label);
        },
        select: function (event, ui) {
           $(e).val(ui.item.label);
           $("input#FLD_WS_ID").val(ui.item.value);
        }
    });
}

You can use the change event :

Triggered when the field is blurred, if the value has changed.

and if the element is not present in the autocomplete list, clear it.

Sample code:

$("#tags").autocomplete({
    source: availableTags,
    minLength: 1,
    focus: function (event, ui) {
        $(event).val(ui.item.label);
    },
    select: function (event, ui) {
        $(event).val(ui.item.label);
        //$("input#FLD_WS_ID").val(ui.item.value);
    },
    change: function (event, ui) {
        if (!ui.item) {
            $(this).val('');
        }
    }
});

Demo: http://jsfiddle.net/IrvinDominin/tLNKv/