function aisatu() {
    alert("やあ");
}

function alertmsg() {
    alert("こんにちは");
}

function addidmsg(ev) {
    var kadai_element = document.getElementById("hello");
    if (kadai_element) {
	kadai_element.innerHTML += " こんにちは";
    }
}

function red() {
var color=document.getElementById("color")
color.style.backgroundColor = "white";document.getElementById("color").style.color  = "black";}

function are() {
var douzo=document.getElementById("douzo")
douzo.style.backgroundColor = "white";document.getElementById("douzo").style.color  = "black";}

function hutatu() {
var douzoda=document.getElementById("douzoda")
douzoda.style.backgroundColor = "white";document.getElementById("douzoda").style.color  = "black";}


function check(ev) {
	var element = (ev.target||ev.srcElement);
	element.style.backgroundColor = "white";
}

function addAll() {
	var i, item;
	var checks = document.getElementsByTagName("span");
	for (i=0; i<checks.length; i++) {
		item = checks[i];
		if (item.getAttribute("class") == "check") {
			item.addEventListener("click", check, false);
		}
	}
}
window.onload = addAll;