Type checking

- [Instructor] At this point we're aware…of many data types in JavaScript.…We know about numbers, strings, booleans,…objects, arrays, and so forth.…There will be times in JavaScript where you want…to find out what a variable contains,…what type of data it contains.…We're going to look at that in this lesson.…JavaScript doesn't care about data types…to the same extent that some languages do.…In other words, it's loosely typed.…There's a video about strongly versus loosely…typed languages later in this course but for now…just know that JavaScript lets you do what…you want with variables.…

So I've made this variable called thing…and I've put the number 12 into it.…But if I decide later I want to change thing…to a string, that's fine, I can do that.…JavaScript doesn't care at all.…During the execution of a program there…will be many times when you're dealing with uncertainty.…You can get to a variable in a particular portion…of your program and you don't necessarily know…what's in there.…And before you act on that data you might need…