如何通过用户代理字符串检测IE7，省略以怪异模式运行的较新IE版本

Question

I need to detect IE7 (and IE6) using the user agent string:

I have made the following regex:

navigator.userAgent.match(/MSIE [67]\./)

However, IE9 in quirks mode also matches the regex with the following user agent :

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 7.1; Trident/5.0; .NET CLR 2.0.50727; SLCC2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.3; .NET4.0C)

I could make two regexes:

navigator.userAgent.match(/MSIE [67]\./) !== null 
  && navigator.userAgent.match(/Trident\/5\.0/) === null

Is there a way I can combine them into one?

Answer 1

Assuming the Trident part always comes after the MSIE part, you can use a lookahead:

/MSIE [67]\.(?!.*Trident[5]\.0)/

I'm not familiar with user agents strings, but I'm guessing that maybe IE10 in quirks mode could have a Trident version > 5, so you could change it to:

/MSIE [67]\.(?!.*Trident[1-9])/

UPDATE: second regex edited to include earlier versions of Trident too, eg Trident/4.0 in IE8, as well as potential later versions >= 10.

UPDATE2: Cleaned up RegEx's to be valid in javascript.

Answer 2

I am posting a JavaScript solution made along with the regex....

function getInternetExplorerVersion()
// Returns the version of Internet Explorer or a -1
// (indicating the use of another browser).
{
  var rv = -1; // Return value assumes failure.
  if (navigator.appName == 'Microsoft Internet Explorer')
  {
    var ua = navigator.userAgent;
    var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
    if (re.exec(ua) != null)
      rv = parseFloat( RegExp.$1 );
  }
  return rv;
}
function checkVersion()
{
  var msg = "You're not using Internet Explorer.";
  var ver = getInternetExplorerVersion();

  if ( ver > -1 )
  {
    if ( ver >= 8.0 ) 
      msg = "You're using a recent copy of Internet Explorer."
    else
      msg = "You should upgrade your copy of Internet Explorer.";
  }
  alert( msg );
}

This solution is actually given my Microsoft, you can refer to this link

Answer 3

也许不是相关但为什么不尝试document&&document.documentMode?document.documentMode:variable ，其中variable将是不是IE的标识符？