// JavaScript Document


// Change background image of page element through CSS
// base on season number (0-3):
// 0 - Spring (default): March, April, May
// 1 - Summer: June, July, Agoust
// 2 - Autumn: September, October, November
// 3 - Winter: December, January, February

function set_image_by_season(element_name) {
	
	var d = new Date();
	var m = d.getMonth();
	
	// Test
	// var m = 6;
	
	var season = 0;
	var bgimgs = new Array(3);
	bgimgs[0] = "url(/images/banner1.jpg)";
	bgimgs[1] = "url(/images/banner2.jpg)";
	bgimgs[2] = "url(/images/banner3.jpg)";
	bgimgs[3] = "url(/images/banner4.jpg)";

	// m = 0 -> January
	if ((m > 4) && (m <= 7)) { 
		season = 1; // summer
	} 
	else if ((m > 7) && (m <= 10)) {
		season = 2; // autumn
	}
	else if ((m > 10) || (m <= 1)) {
		season = 3; // winter
	};
	
	var element = document.getElementById(element_name);
	element.style.backgroundImage = bgimgs[season];
}