js in three cycles

1.while:

          Syntax structure: while (condition) {code block; change condition}

                       Step: 1 initializes the variable determination condition 2. 3. 4. The initial condition block of code to change the determination condition 5

 

2.do while

          Syntax structure: do {code block} while (condition)

                      Steps: 1. Initialize a variable performed unconditionally 2. 3. 4. Condition determination block of code changing initial conditions The determination condition 6

 

3.for

         Syntax structure: for (initialize variables; Analyzing conditions; initialize variables changed) {} ​​block

                     Step: 1 initializes the variable determination condition 2. 3. 4 block of code initializes variables change