So please tell us your "Mongol" version of the invasions:
(1) The Mongol invasions of Dai Viet (Vietnam)
(2) The Mongol invasions of Champa (ceased to exist as it is now fully annexed by Vietnam)
(3) The Mongol invasion of Java (modern-day Indonesia)
(4) The Mongol invasion of Burma (modern-day Myanmar)
(5) The Mongol invasion of Nanchao (southern China)
(6) The Mongol invasion of Laos???
(7) The Mongol invasion of the Kingdom Mong Mao (present-day northern Thailand)
The Mongol Dynasty in China and the Khmer Empire is an interesting one. It is by the recorded journal of the ambassador from the Mongol court that the people of the world today can have a glimps of what it was like during the heyday of the Khmer Empire.
However, I don't know whether this information below is accurate or not, but I was very surprise to find that the Mongols in China wanted the Khmer Empire to be its vassal.
• Khmer empire. In 1278, a Mongol envoy was executed by the Khmer king. An envoy was sent again to demand submission when the Yuan army was besieging the fortress in Champa. 100 Mongol cavalries sent to Khmer after the imprisonment of the second envoy. They were ambushed and destroyed by the Khmers. However, the King of Khmer Empire sent tribute in 1285 due to his war-like neighbours and Kublai Khan's rage. http://en.wikipedia.org/wiki/Mongol_Empire
If the information is correct, then it was a wise choice for the Khmer King to avoid any conflicts with the Mongols because accrodiing to the Mongol embassador to the kingdom, the Khmer Empire was ravaged by the Thai troops. So it was best to deal with ONE FOE and not two at the same time.
Your contribution is appreciated.