if (document.images) 	{
	shachoImg = new Image
	kihonImg = new Image
	keieiImg = new Image
	eigyoImg = new Image
	
	shachoImg.src = "images/shacho_o.gif"
	kihonImg.src = "images/kihon_o.gif"
	keieiImg.src = "images/keiei_o.gif"
	eigyoImg.src = "images/eigyo_o.gif"
	
	}

else {
	shachoImg.src = ""
	kihonImg.src = ""
	keieiImg.src = ""
	eigyoImg.src = ""

	}