/**
 * 电算科使用的 js程序
 */
 
/*图片自由移动功能
  Begin
*/
var isNS = ((navigator.appName == "Netscape") && (parseInt(navigator.appVersion) >= 4));
var _all = '';
var _style = '';
var wwidth, wheight;
var ydir = '++';
var xdir = '++';
var id1, id2, id3;
var x = 1;
var y = 1;
var x1, y1;
if(!isNS) {
	_all='all.';
	_style='.style';
}
function getwindowsize() {
	clearTimeout(id1);
	clearTimeout(id2);
	clearTimeout(id3);
	if (isNS) {
		wwidth = window.innerWidth - 550;
		wheight = window.innerHeight - 500;
	} 
	else {
		wwidth = document.body.clientWidth - 550;
		wheight = document.body.clientHeight - 500;
	}
	id3 = setTimeout('randomdir()', 20000);
	animate();
}
function randomdir() {
	if (Math.floor(Math.random()*2)) {
		(Math.floor(Math.random()*2)) ? xdir='--': xdir='++';
	} 
	else {
		(Math.floor(Math.random()*2)) ? ydir='--': ydir='++';
	}
	id2 = setTimeout('randomdir()', 20000);
}
function animate() {
	eval('x'+xdir);
	eval('y'+ydir);
	if (isNS) {
		pic1.moveTo((x+pageXOffset),(y+pageYOffset))
	} 
	else {
		pic1.pixelLeft = x+document.body.scrollLeft;
		pic1.pixelTop = y+document.body.scrollTop;
	}
	if (isNS) {
		if (pic1.top <= 5+pageYOffset) ydir = '++';
		if (pic1.top >= wheight+pageYOffset) ydir = '--';
		if (pic1.left >= wwidth+pageXOffset) xdir = '--';
		if (pic1.left <= 5+pageXOffset) xdir = '++';
	} 
	else {
		if (pic1.pixelTop <= 5+document.body.scrollTop) ydir = '++';
		if (pic1.pixelTop >= wheight+document.body.scrollTop) ydir = '--';
		if (pic1.pixelLeft >= wwidth+document.body.scrollLeft) xdir = '--';
		if (pic1.pixelLeft <= 5+document.body.scrollLeft) xdir = '++';
	}
	id1 = setTimeout('animate()', 30);
}

/*End */