Use onkeypress to force IE to do onchange when RETURN is pressed (resolves bug reproted at https://sourceforge.net/projects/mathjax/forums/forum/948701/topic/3862906)

git-svn-id: https://mathjax.svn.sourceforge.net/svnroot/mathjax/trunk@608 b8fd5906-0fad-46e2-a0d3-10d94ff285d1

mathjax/test/sample-dynamic.html

@@ -50,5 +50,18 @@ Type some TeX code and press RETURN:<br/>
 You typed: ${}$
 </div>
 
+<script>
+//
+//  IE doesn't fire onchange events for RETURN, so
+//   use onkeypress to do a blur (and refocus) to
+//   force the onchange to occur
+//
+if (MathJax.Hub.Browser.isMSIE) {
+  window.MathInput.onkeypress = function () {
+    if (window.event && window.event.keyCode === 13) {this.blur(); this.focus()}
+  }
+}
+</script>
+
 </body>
 </html>