$(document).ready(function(){
    $(".auto_complete").autocomplete(
    {
        source: function(request, response) 
        {
            $.getJSON("http://completion.amazon.co.uk/search/complete?method=completion&q="+escape(request.term)+"&search-alias=aps&mkt=4&x=?", function(data){
				response(completion[1]);});
        },
        select: function(value, data) {
            document.getElementById("head_suche_w").value = data.item.value;
            $(this).closest('form').trigger('submit');
        },
        minLength: 2,
        delay: 50
     }).keydown(function(e) 
     {
        if (e.keyCode === 13) 
        {
            $(this).closest('form').trigger('submit');
        }
     });
});