js 判断浏览器

function isBrowser() {
var userAgent = navigator.userAgent;
//微信内置浏览器
if(userAgent.match(/MicroMessenger/i) == 'MicroMessenger') {
return "MicroMessenger";
}
//QQ内置浏览器
else if(userAgent.match(/QQ/i) == 'QQ') {
return "QQ";
}
//Chrome
else if(userAgent.match(/Chrome/i) == 'Chrome') {
return "Chrome";
}
//Opera
else if(userAgent.match(/Opera/i) == 'Opera') {
return "Opera";
}
//Firefox
else if(userAgent.match(/Firefox/i) == 'Firefox') {
return "Firefox";
}
//Safari
else if(userAgent.match(/Safari/i) == 'Safari') {
return "Safari";
}
//IE
else if(!!window.ActiveXObject || "ActiveXObject" in window) {
return "IE";
}
else {
return "未定义:"+userAgent;
}
}