var MzBrowser={};(function()
{
if(MzBrowser.platform) return;
var ua = window.navigator.userAgent;
MzBrowser.platform = window.navigator.platform; MzBrowser.firefox = ua.indexOf("Firefox")>0;
MzBrowser.opera = typeof(window.opera)=="object";
MzBrowser.ie = !MzBrowser.opera && ua.indexOf("MSIE")>0;
MzBrowser.mozilla = window.navigator.product == "Gecko";
MzBrowser.netscape= window.navigator.vendor=="Netscape"; if(MzBrowser.firefox) var re = /Firefox(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.ie) var re = /MSIE( )(\d+(\.\d+)?)/;
else if(MzBrowser.opera) var re = /Opera(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.netscape) var re = /Netscape(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.mozilla) var re = /rv(\:)(\d+(\.\d+)?)/; if("undefined"!=typeof(re)&&re.test(ua))
MzBrowser.version = parseFloat(RegExp.$2);
})();alert(MzBrowser.ie)
alert(MzBrowser.version);//节选自 jsframework
{
if(MzBrowser.platform) return;
var ua = window.navigator.userAgent;
MzBrowser.platform = window.navigator.platform; MzBrowser.firefox = ua.indexOf("Firefox")>0;
MzBrowser.opera = typeof(window.opera)=="object";
MzBrowser.ie = !MzBrowser.opera && ua.indexOf("MSIE")>0;
MzBrowser.mozilla = window.navigator.product == "Gecko";
MzBrowser.netscape= window.navigator.vendor=="Netscape"; if(MzBrowser.firefox) var re = /Firefox(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.ie) var re = /MSIE( )(\d+(\.\d+)?)/;
else if(MzBrowser.opera) var re = /Opera(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.netscape) var re = /Netscape(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.mozilla) var re = /rv(\:)(\d+(\.\d+)?)/; if("undefined"!=typeof(re)&&re.test(ua))
MzBrowser.version = parseFloat(RegExp.$2);
})();alert(MzBrowser.ie)
alert(MzBrowser.version);//节选自 jsframework
{
......
})();
这是什么语法阿,解释一下好吗
(function(){})(); //声明一个无名函数,并且运行它。目的是防止里面的一些变量变成全局变量