js image onload print

gistfile1.js

(function(){
	var loc = document.location.search,
		t = new Date(),
		img = new Image(),
		src = '';

	if(loc.indexOf('page=hoge') > -1){
		src = 'images/hoge/print.jpg'+'?'+t.getTime();

	}else if(loc.indexOf('page=fuga') > -1){
		src = 'images/fuga/print.jpg'+'?'+t.getTime();
	};

	if(src !== ''){
		img.alt = '';
		img.src = src;
		img.onload = function(){
			document.getElementsByTagName('body')[0].appendChild(img);
			setTimeout( function(){
				window.print();
			},300);
		};
	}
}());