Something

var place_input_count=1;
var add_place_input=function(){
	var new_input=document.createElement("input");
	new_input.setAttribute("id", "place_input"+place_input_count);
	new_input.setAttribute("type", "text");
	new_input.setAttribute("size", "7");
	new_input.onkeydown=function(){if (!this.already_added) add_place_input(); this.already_added=1;}
	$('places').appendChild(new_input);
	
	
	var autocomplete_choices=document.createElement("div");
	autocomplete_choices.setAttribute("class", "autocomplete");
	autocomplete_choices.setAttribute("id", "autocomplete_choices"+place_input_count);
	$('places').appendChild(autocomplete_choices);
	
	
	new Ajax.Autocompleter(
		"place_input"+place_input_count,
		"autocomplete_choices"+place_input_count,
		"<?=URL?>_find-place/",
		{
			paramName: "q",
			/*minChars: 1,
			indicator: 'loading'*/
		}
	);
	place_input_count++;
}