Process Control-loop (for) statements in JS

For statement:

1 <script>2  /*for  (EXP1;EXP2;EXP3) {3        loop body; 4    }5    EXP1: Unconditionally executes the first expression 6    EXP2: Determines whether the loop body can be executed  7    EXP3: Do an incremental operation/     8 </script>

We want to print a word like: document.write ("Welcome to Ziksang Blog")

If we want to print the same 100 sentences, we have to print 100 times in this way

If you use a For loop, consider the following example

1  <script>2for          (var i = 1; i<=100; i++) {3                   document.write ("Welcome to Ziksang Blog")4              }5      </script>

If we want to print 1~100 or 100~1, take a look at the example below

1 //If we don't use a for loop, we're going to do it 100 times.2document.write ("0")3      //........ Perform 100 operations4       for(vari = 0; i<=100; i++) {//from 0 to5 document.write (i)6      }7       for(vari = 100; i>=0; i--) {//from 100 to 08 document.write (i)9}

Print the sum of 1~100

1 <script>2          var sum = 03for          (var i = 1;i<=100; i++) {4                 sum + =I5             }6          document.write (sum)7  </script>

We use the For statement to find all the odd and even numbers of a 1~100

1  <script>2for                    (var i =1;i<=100;i++) {3                        if(i %2 = = 1) {     //Use the IF statement to determine the odd number, if it is odd, execute the following code block statement  4                           document.write (i)  5                       }                  //Returns all odd  6                   }   7  </script>

1<script>2                     for(varI =1;i<=100;i++){3                        if(i%2 = = 1) {//use a judgment statement to determine if it is odd, if it is odd to return True, execute a code block statement, continue jumps out of the loop, and proceeds to the next loop4                           Continue5                        }6 document.write (i)// return all even 7                    }8</script>

We use break to insert a for loop to see the effect

1<script>2                  for(vari = 0; I <10;i++){3                         if(i==3){4                                  Break     //jump out of loop when i=3, stop looping5                             }6document.write (i)//at this point I output is 0,1,27                     }8</script>

We use continue to insert a For loop to see the effect

1<script>2 3              for(vari = 0; I <10;i++){4                 if(i==3){5                     Continue     //when i=3 jump out of the loop statement, continue to start the loop, the direct execution of the flase (i<10);6                 }7document.write (i)//at this point I output is 0,1,2,4,5,6,7,8,98             }9</script>

Nested loops for a for statement

1<script>2                for(varI =1;i<3;i++){3document.write ("Outer loop" +i+ "times" + "</br>")//execute the outer statement first4                                                              //execute the outer statement again5                       for(varJ =1;j<=3;j++){6document.write ("Inner Loop" +j+ "times" + "</br>")//execute the inner statement again7}//execute the inner statement again8document.write ("//the last direct judgment is false .9               }Ten  One</script>

We use a For statement to loop through a 3-line 30-case table with the following code:

1<table border= "1" cellpadding= "0" bgcolor= "Aqua" width= "80%" >2<script>3                  for(vari = 1; i<=3;i++) {//We first execute the first line, the so-called execution once, then execute the second line, the so-called second4document.write ("<tr>")5                        for(varJ=1; j<=30;j++) {//30 cases were circulated and 30 cases were recycled.6document.write ("<td>x</td>")7                       }8document.write ("</tr>")9                 }Ten</script> One</table>

Once again, we will strengthen the function above, using a for statement to loop a 99 multiplication table, the code is as follows:

1<table border= "1" cellpadding= "0" bgcolor= "Aqua" width= "40%" >2<script>3                      for(varI =1;i<=9;i++){4document.write ("<tr>")//First line <tr>5                              for(varj = 1; j<=i;j++) {//<td>1*1=1</td>6document.write ("<td>" +i+ "*" +j+ "=" + (i*j) + "</td>")7                             }8document.write ("</tr>")//</tr>9}//keep doing this loop until the condition is falseTen</script> One</table>

Process Control-loop (for) statements in JS