Most web browsers have mature supportEarly implementations (such as Mozilla 0.7 and Opera 6.0, both released in 2001) do not incrementally render XHTML as it is received over the network, giving a degraded user experience; see the Mozilla Web Author FAQ. Later browsers such as Opera 9.0, Safari 3.0, and Firefox 3.0 do not have this issue. for all of the possible XHTML media types. The notable exception is Internet Explorer versions 8 and earlier by Microsoft; rather than rendering application/xhtml+xml content, a dialog box invites the user to save the content to disk instead. Both Internet Explorer 7 (released in 2006) and Internet Explorer 8 (released in March 2009) exhibit this behavior. Microsoft developer Chris Wilson explained in 2005 that IE7's priorities were improved browser security and CSS support, and that proper XHTML support would be difficult to graft onto IE's compatibility-oriented HTML parser; however, Microsoft added support for true XHTML in IE9.
