$(function(){
	bind_img_with_id("teacher_img");
	bind_img_with_id("student_img");
	bind_img_with_id("parent_img");

	bind_img_with_id("teacher_img_desc_area");
	bind_img_with_id("student_img_desc_area");
	bind_img_with_id("parent_img_desc_area");
});

function bind_img_with_id(id)
{
	var obj = $('#'+id)[0];
	obj.onmouseover = function(){show_over(id);}
	obj.onmouseout = function(){hide_over(id);}
}

function get_target_imgover_id(id)
{
	var target = '';
	switch(id)
	{
		case "teacher_img":
		case "teacher_img_desc_area":
			target = "teacher_over";
			break;
		case "student_img":
		case "student_img_desc_area":
			target = "student_over";
			break;
		case "parent_img":
		case "parent_img_desc_area":
			target = "parent_over";
			break;
	}
	return target;
}

function show_over(id)
{
	var target = get_target_imgover_id(id);
	$('#'+target).each(function(){
		this.style.visibility = "visible";
	});
}

function hide_over(id)
{
	var target = get_target_imgover_id(id);
	$('#'+target).each(function(){
			this.style.visibility = "hidden";
	});
}