Textbox autocomplete clears if not match in option value

Question

I have here an autocomplete function. What I need is if the value that writing in textbox is not match on option value clear the textbox. Here's what I got right now http://jsfiddle.net/qv94t/

The textbox not allowing even the value is in the options.

Here's my code

<form id="register_form" name="register_form">
<input list="language" id="none">
<datalist id="language" name="options">
<option value="Alabama">Alabama</option>
<option value="Alaska">Alaska</option>
<option value="Arizona">Arizona</option>
<option value="kansas">kansas</option
<option value="California">California</option>
</datalist>
</form>

<script>
var validOptions = $("form#register_form input[name='options']").val();
previousValue = "";

$('#none').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;
    }
});
</script>

Answer 1

I think this is what you are looking for:

http://jsfiddle.net/juvian/qv94t/3/

Your validOptions was undefined, so was not working properly.

var validOptions =[];
$("#language option").each(function(){
    validOptions.push($(this).val())      
});

Hope it helps!

Answer 2

Get rid of this code

if (!isValid) {
    this.value = previousValue
} else {
    previousValue = this.value;
}

it is the one causing trouble

Demo Fiddle

Answer 3

just remove this.value = previousValue

here is updated fiddle, http://jsfiddle.net/qv94t/2/

var validOptions = $("form#register_form input[name='options']").val();
previousValue = "";

$('#none').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;
    }
});

Hope this helps..! :D