jQuery UI AutoComplete: Only allow selected valued from suggested list

Question

I am implementing jQuery UI Autocomplete and am wondering if there is any way to only allow a selection from the suggested results that are

Answer 1

http://jsfiddle.net/pxfunc/j3AN7/

var validOptions = ["Bold", "Normal", "Default", "100", "200"]
previousValue = "";

$('#ac').autocomplete({
    autoFocus: true,
    source: validOptions
}).keyup(function() {
    var isValid = false;
    for (i in validOptions) {
        if (validOptions[i].toLowerCase().match(this.value.toLowerCase())) {
            isValid = true;
        }
    }
    if (!isValid) {
        this.value = previousValue
    } else {
        previousValue = this.value;
    }
});