Clarification about JavaScript fundamental syntax and its impact on OOP.

Hi Nimish Hathalia

It looks like you're gaining a really good grasp of the concepts.

Let's start backwards with your 3rd point. You seem to have a solid understanding of which to use where and why. The only thing I think I'd point out is that when you talk about "chaining" with parentheses, that may be a be misleading as you're still using the () with a function. getElementById() is a function call and the () is holding the argument being passed to it. and the function declaration is using () to hold the parameter for the function.

Now back to the first point. My preference are double quotation marks, unless I need to use double quotations inside of a declared string. I then use single to enclose the string and double inside the string, rather than escaping the inner ones.
e.g. "A string with no quotes in side." ===> 'A string with a quote from someone saying "Use Doubles here" and so on.'
Really, in JavaScript, there is no real "rule-of-thumb". The important thing is to be consistent and always go by the style-sheet put out by the company or group you are working with. If you move to other languages, do a quick search on that language's style-guide as there may be some preference based on language (i.e. Python).
Accent mark, are really backticks. In JavaScript, they are used to create Template Literals, which contain placeholders. You can read more about Template Literals on MDN.

For your second point. Honestly, that's a bit more 'confusing' (for lack of a better word). Some languages demand them and will throw syntax errors without them. Some languages don't use a single one and throw syntax errors in you do use them. Python, for example allows them, but they aren't really used and are not standard practice. Java, they are essential... and then there is JavaScript.
In JavaScript, semicolons are Statement enders (not terminators). And for every person you find that say to avoid using them, you will find one that says you absolutely should use them. There are some places in JavaScript where they are needed (i.e. loop conditions/expressions), but for the most part, there are technically optional, as the interpreter automatically inserts the semicolon at the end of each line for you.
As for what is the convention? ... Well, that is currently a very highly debated topic. I personally use them, but I know many who don't. I think for now, this will come down to your personal preference. Just be consistent and follow your group (if you're woking with one).

Great questions!!

I hope I was able to help. :)