Control structures

If ... else

if (condition) {
  statements
} else {
  statements
}

Switch statement

switch (expression) {
  case label1 :
    statements;
    break;
  case label2 :
    statements;
    break;
  default :
    statements;
}

Actually, break; is optional. However leaving it out isn't recommended in most cases since otherwise code execution will continue to the body of the next case … : .

For loop

for ([initial-expression]; [condition]; [increment-expression]) {
  statements
}

For ... in loop

This loop goes through all enumerable properties of an object (or elements of an array).

for (slot in object) {
  statements involving object[slot]
}

While loop

while (condition) {
  statements
}

Do ... while

do {
  statements
} while (condition);