html5 canvas文字变换切换特效

js代码

<script type="text/javascript" src="js/js.js"></script>
<script type="text/javascript" src="js/config.js"></script>
<script type="text/javascript">
var isDesktop = navigator['userAgent'].match(/(ipad|iphone|ipod|android|windows phone)/i) ? false : true;
var fontunit        = isDesktop ? 20 : ((window.innerWidth>window.innerHeight?window.innerHeight:window.innerWidth)/320)*10;
document.write('<style type="text/css">'+
'html,body {font-size:'+(fontunit<30?fontunit:'30')+'px;}'+
(isDesktop?'#welcome,#GameTimeLayer,#GameLayerBG,#GameScoreLayer.SHADE{position: absolute;}':
'#gamepage,#gameend,#GameLayerBG,#GameScoreLayer.SHADE{position:fixed;}@media screen and (orientation:landscape) {#landscape {display: box; display: -webkit-box; display: -moz-box; display: -ms-flexbox;}}')+
'</style>');
</script>