How to detect browser using javascript

You can detect your running browser as follows:

var browser = navigator.userAgent;

if(browser.indexOf('MSIE') !=-1)
        alert('You are using Internet Explorer');
else if(browser.indexOf('firefox') !=-1)
{
        alert('You are using Firefox');
}
else if(browser.indexOf('opera') !=-1)
{
        alert('You are using Opera');
}