There was some debate back when this was first revealed in 2009, but the use of ChromeFrame is still relevant for some organizations that are stuck on older browsers for legacy applications.
<meta http-equiv="X-UA-Compatible" content="chrome=1" /><!-- this is for all versions of IE -->
<meta http-equiv="X-UA-Compatible" content="chrome=IE6" /><!-- this is for IE6 and lower -->
<meta http-equiv="X-UA-Compatible" content="chrome=IE7" /><!-- this is for IE7 and lower -->
<meta http-equiv="X-UA-Compatible" content="chrome=IE8" /><!-- this is for IE8 and lower -->
<meta http-equiv="X-UA-Compatible" content="chrome=IE9" /><!-- this is for IE9 and lower -->
<meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=IE6" /><!-- this is for IE9 and lower, passes Edge to others -->
NOTES:
- Installation can be done without Administrative rights on the Windows OS.
- Installation will append the ‘chromeframe’ version to the ‘User-Agent’ HTTP header sent by the browser to allow it to be parsed.
REFERENCES: