JavaScript Basic Syntax Three

First, the circulation

Loop structure: An operation that executes repeatedly when a specific condition is met. Loop four elements: Loop variable, loop condition, loop increment, loop body.

First type: While loop. while (conditional expression) {loop body;}.

First step: Define the Loop variable

var count = 1;

Part II: Judging the cycle conditions

while (Count <= 5) {

Part III: Circulation body

Console.log ("Running Circle")

Fourth step: Loop increment

count++;

}

Use while to print a multiple of 1~100 that is not 7 and does not contain a number of 7

var num = 1;
While (num <=) {
var a = num% 7! = 0;
var b = num%! = 7;
var c = Math.floor (NUM/10)! = 7;
if (a && b && c) {
console.log (num);
                    }
num++;
                 }

The second type: Do-while cycle. do{Loop body}while (conditional expression).

var a = 0;
do{
Console.log (a);
a++;
}
while (a < 10)

The third type: For loop. for (loop variable loop condition loop increment) { loop body }

Use while to print a multiple of 1~100 that is not 7 and does not contain a number of 7

For (var i = 1; i <=; i++) {
var a = i% 7!=0;
var b = i%! = 7;
var c = Math.floor (I/10)! = 7;
if (a && b && c) {
Console.log (i)
                       }
                }

Second, break and continue.

bresk:1. In switch, used to end the entire branch statement.

2. In the loop, a break is encountered, the statement following it is no longer executed, and the entire loop is ended.

Continue: In the loop, the continue is encountered, and the statement behind it is not executed and jumps out of the loop.

Random number

Math.random (); Used to return a random number between a 0~1, including 0, but excluding 1.

1. Generate an integer randomly between [1,10]
var random = Math.floor (Math.random () * 10) + 1;
alert (random);

2. Generate an integer randomly between [1,100]

var random = Math.floor (Math.random () * +) + 1;
alert (random);

3. Generate an integer randomly between [10,20]

var random = Math.floor (Math.random () * one) + ten;
alert (random);

4. Generate an integer randomly between [12,38]

var random = Math.floor (Math.random () * 27) + 12;
alert (random);

5, Math.max to find the maximum value

var maxValue = Math.max (12,56,7987,121,54646,8975465);
alert (MaxValue);

6, Math.min to find the minimum value

var minValue = math.min (0,454,212,-1847,-21,42);
alert (MinValue);

7, Math.ceil Upward rounding
var value2 = Math.ceil (3.1);
alert (value2);

8. Math.Round Rounding

var value3 = Math.Round (4.2);
var value4 = Math.Round (5.8);
var a = Math.Round (4.4);
alert (VALUE3);
alert (VALUE4);
alert (a);

Iv. adding the specified content to an element

InnerHTML

Get element

var odiv = document.getElementById (' Div1 ');

InnerHTML: Adding the specified content to an element

odiv.innerhtml = "What to add"

JavaScript Basic Syntax Three