有人能解释一下像“for (;;)”这样的循环的语法吗

Question

Can someone explain me the Syntax of a for-loop like "for (;;)" what i need to know is whether the header of a for-loop like "for (;;)" is having empty-statements or not.

I searched the ECMAScript specification about what will happen if all the optional expressions within the for-loop's header is skipped like for (;;) in the specification but i still didnt find about it

can someone explain me about this even the specification haven't mentioned that a for-loop like for (;;) loops/runs infinite times

and i need to know one last thing why people call the header of a for-loop is having Expression's i see that the syntax of a for loop allows us to write declarations like var i = 0 in the header of the for-loop and i see the for-loops syntax allows us to write semicolons; in its header only statements require semicolons does that mean all the syntax within the for-loop's header is having Statements

Answer 1

In a standard for loop definition, it would go as follows:

for (var i = 0; i < 5; i++)
{

   //Do something here

}

You have your statement being defining i as 0 ( var i = 0 ). Then, there is the condition/expression that the for loop checks each time as it runs, which in this example checks that i is less than 5 ( i < 5 ).

So, to address the first part of your question, when you define a for loop as for(;;) , you are simply defining a loop with no condition that must be met. Therefore, it continues to run/loop forever. This can be done because all parts of the for loop definition are optional. So, there are no " empty-statements ". It is simply defining the for loop without the optional arguments. We fill it in with semicolons instead in order to represent the transition between the empty arguments.