/* ******************************************************
	部局メインイメージ変更用スクリプト(bukyokuImageChange.js)
********************************************************* */

function bukyokuImageChange(img1, img2, img3, defaultImg){
	mn=1;
	mx=1;
	
	if(img1){
		mx=1;
	}
	if(img2){
		mx=2;
	}
	if(img3){
		mx=3;
	}
	
	r=Math.round(Math.random()*(mx-mn))+mn;

	if(r==1){
		if(img1){
			document.getElementById("bukyoku").style.backgroundImage="url("+img1+")";
		}else{
			document.getElementById("bukyoku").style.backgroundImage="url("+defaultImg+")";
		}
	}else if(r==2){
		if(img2){
			document.getElementById("bukyoku").style.backgroundImage="url("+img2+")";
		}else{
			document.getElementById("bukyoku").style.backgroundImage="url("+defaultImg+")";
		}
	}else if(r==3){
		if(img3){
			document.getElementById("bukyoku").style.backgroundImage="url("+img3+")";
		}else{
			document.getElementById("bukyoku").style.backgroundImage="url("+defaultImg+")";
		}
	}
}