jQuery 1.9 Autocomplete 点击提示全部

<input id="autocomplete"/> <input id="submit" type="submit"/>

var source = ['One', 'Two', 'Three', 'Four'];

var firstVal = source[0];

$("input#autocomplete").autocomplete({
minLength: 0,
source: source
}).focus(function() {
$(this).autocomplete("search", "");
});