Something

		var task_count = 1;

		function add_task()
		{
			var table, tbody, tr, th, td, field;
			var node = document.getElementById("tasks");
			
			task_count += 1;
			
			// initialize
			table = document.createElement("TABLE");
			tbody = document.createElement("TBODY");
			tr = document.createElement("TR");
			th = document.createElement("TH");
			td = document.createElement("TD");
			
			// make task name filed
			field = document.createElement("INPUT");
			field.setAttribute("type", "text");
			field.setAttribute("name", "task_"+ task_count);
			field.setAttribute("size", 25);
			
			th.appendChild( document.createTextNode("Task Type") );
			td.appendChild( field );
			
			tr.appendChild( th );
			tr.appendChild( td );
			tbody.appendChild( tr );
			
			// make task description field
			tr = document.createElement("TR");
			th = document.createElement("TH");
			td = document.createElement("TD");
			
			field = document.createElement("TEXTAREA");
			field.setAttribute("name", "task_description_"+ task_count);
			field.setAttribute("cols", 50);
			field.setAttribute("rows", 10);
			
			th.appendChild( document.createTextNode("Task Description") );
			td.appendChild( field );
			
			tr.appendChild( th );
			tr.appendChild( td );
			tbody.appendChild( tr );
			
			table.appendChild( tbody );
			node.appendChild( table );
		}