function toggleCategory(categoryElementId, num_category) {
for(var cnt = 1; cnt <= num_category; cnt ++){
		if(cnt == categoryElementId && document.getElementById( "category-" + categoryElementId ).style.display == "none"){
			document.getElementById( "category-" + categoryElementId ).style.display = "";
		}
		else {
	        document.getElementById( "category-" + cnt ).style.display = "none";
		}
	}
}