All browsers support the lang attribute .
Notes : lang attribute in the following tag is invalid : <base>, <br>, <and <script>.
According to the W3C recommendation, you should by <html> lang attribute tag for each page in the main language statement, such as:
<! DOCTYPE HTML>
<HTML lang = "EN" >
// description of the English code page mode
........
</ HTML>
In XHTML, the following manner using language statement <html> tag:
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
...
</html>
Reference lang language code which:
http://www.w3school.com.cn/tags/html_ref_language_codes.asp