I have no experience in programming in JS, but from what programming experience I do have, I can say that the first line is talking about an object, which is the browser that is currently running. It says that if the current browser is any sort of mobile browser, that's the this.mobile.browser.any() part of the code, it should do the following string of commands that are within the {}.
The command it should do is set the browser to full screen upon the program entering it. In most languages the bit that starts
is always referring to the current thing the program is working with, in this case the browser. In this case there is only one command to do if the original IF question was true, so there is only the one line. The last line with the } is just there to tell the program that all of the conditional IF commands have been processed.
By commenting out the first line of the code you remove the conditional question, is this a mobile browser. That question isn't asked, instead the command is applied to all types of browser. The last line is commented out because telling the program that a special section of code is complete, without starting a special section will always get messy. You pretty much always have opening { all over the code. Adding what is effectively a random closing } will stop something early. Sometimes as a programmer getting the opening and closing braces to match correctly is one of the hardest parts of debugging a program.
Adding comments to programs is useful since it can help remind you, or more importantly your replacement 30 years down the road, of what you were thinking when you wrote the code. In most programming languages the // tell the system that everything else on the line after this point is comment. Many languges also allow you to use /* as the start of a multi line comment, and then
on
another line you can use */ to close the block of comment. In a perfect world those three lines of code might look something like this:
if (this.mobile.browser.any()) { //If "this" is a mobile browser do the following
this.fullscreen.enter(); //Set "this" to full screen on enter
} //End of IF statement
Commenting out whole lines rather than deleting is good because if you got it wrong, and you broke it, repaing it is as simple as removing the comment indicators. But always remember to remove comments at both ends, or you just break it more.
Oh and where I mention what goes wrong when you get adding/removing the comments incorrect comes from long and hard personal experiance.
Alan
