jquery autocomplete options not working

I'm using jquery autocomplete

<script src='http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js'></script>
<script src='http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.2/jquery-ui.min.js'></script>

Everything is working Ok., but now I'm trying to add a minChars option which doesn't do anything. My code looks like this:

$( "#searchid" ).autocomplete({
    source: "/autocomplete_url.php?more=1", 
    minChars:6,             
开发者_高级运维    select: function(event, ui) { 
               $("#searchid").val(ui.item.value);
               $("#formid").submit(); 
            }
});

Everything is working, except it disregards the options I'm adding. Why/How can I debug the problem?

UPDATE: according to the answer below, I've moved to use minLength instead. I've tried adding in two different ways but it doesn't work :/ This is my "new" code:

    $( ".selector" ).autocomplete({ minLength: 6 });        
    $( "#searchid" ).autocomplete({
        source: "/autocomplete_url.php?more=1", 
        minLength:6,        
        select: function(event, ui) { 
               event.preventDefault();
               $("#searchid").val(ui.item.value);
               $("#formid").submit(); 
            }
    });

Thanks

---

It's not minChars but minLength
see http://jqueryui.com/demos/autocomplete/#option-minLength

$( ".selector" ).autocomplete({ minLength: 0 });

---

Generally, if you want to manipulate the form element that the autocomplete itself is attached to, you should include a

event.preventDefault();

inside your select: function(event, ui){} block. Otherwise the default autocomplete behaviour will conflict with your code, as it's also trying to set that value.

---

Make sure that your source returns JSON with the keys: id, value, and label. If it doesn't you'll need to use a callback function as your source. Check out this article on nettus:

http://net.tutsplus.com/tutorials/javascript-ajax/how-to-use-the-jquery-ui-autocomplete-widget/