js浏览器全屏的是实现

项目里面有一个需要实现浏览器全屏 也就是F11的效果

主流的浏览器都支持  可恶的IE9以下不支持！！！！

$("#fullscreen").bind("click",function () {
     if($("#fullscreen").text() == "全屏显示"){
         var a = document.documentElement;
         //W3C
         if (a.requestFullscreen) {
             a.requestFullscreen();
         }
         //FireFox
         else if (a.mozRequestFullScreen) {
             a.mozRequestFullScreen();
         }
         //Chrome等
         else if (a.webkitRequestFullScreen) {
             a.webkitRequestFullScreen();
         }
         //IE11
         else if (a.msRequestFullscreen) {
             a.msRequestFullscreen();
         }
         $("#fullscreen").text("关闭全屏");
     }else if($("#fullscreen").text() =='关闭全屏' ){
         if (document.exitFullscreen) {
             document.exitFullscreen();
         }
         else if (document.mozCancelFullScreen) {
             document.mozCancelFullScreen();
         }
         else if (document.webkitCancelFullScreen) {
             document.webkitCancelFullScreen();
         }
         else if (document.msExitFullscreen) {
             document.msExitFullscreen();
         }
         $("#fullscreen").text('全屏显示')

     }
})