function ajaxDo(option_type)
	{ 
		var req = null; 
		var option_type = option_type;
		var option_id = option_id;
		var link = option_type +".php";

		if(window.XMLHttpRequest)
			req = new XMLHttpRequest(); 
		else if (window.ActiveXObject)
			req  = new ActiveXObject("Microsoft.XMLHTTP"); 

		req.onreadystatechange = function()
		{ 
			if(req.readyState == 4)
			{
				if(req.status == 200)
				{
					if(option_type == 'engines')
					{
						document.getElementById("engines").innerHTML=req.responseText;
					}
					if(option_type == 'engines_store')
					{
						document.getElementById("engines_store").innerHTML=req.responseText;
					}
				}	
			} 
		}; 
		req.open("POST", link, true); 
		req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); 
		req.send(null); 
	}