function onConstruction() {
	document.getElementById("btn_construction").style.background="url(images/btn_construction2.jpg) no-repeat left top;";
	}
function outConstruction() {
	document.getElementById("btn_construction").style.background="url(images/btn_construction1.jpg) no-repeat left top;";
	}
function onRent() {
	document.getElementById("btn_rent").style.background="url(images/btn_rent2.jpg) no-repeat left top;";
	}
function outRent() {
	document.getElementById("btn_rent").style.background="url(images/btn_rent1.jpg) no-repeat left top;";
	}
function onDiary() {
	document.getElementById("btn_diary").style.background="url(images/btn_diary2.jpg) no-repeat left top;";
	}
function outDiary() {
	document.getElementById("btn_diary").style.background="url(images/btn_diary1.jpg) no-repeat left top;";
	}

function onAboutus() {
	document.getElementById("btn_overview").style.background="url(images/btn_overview2.jpg) no-repeat left top;";
	}
function outAboutus() {
	document.getElementById("btn_overview").style.background="url(images/btn_overview1.jpg) no-repeat left top;";
	}