Singapore vs. Malaysia

Hey guys
wanted to ask questions. After coming to this forum i found out that Malaysia and Singapore are not exactly on friendly terms.
-Has there ever been a war between them? or a warlike situation?
-Whats the origin of the conflict? how it got started and what were the reasons?
-How bad is the situation and the tension today? i mean what are the chances of war happening and what is the preparedness of both the countries in respect to their air arms and a naval capabilities.

Remember i dont know anything of the issue so please bare my ignorance and curiosity… trying to learn as we go here.