19.8.13js cycle

js cycle are:

for loop:

for (EXP1; EXP2, EXP3) { 
 loop body; 
} 
EXP1: unconditional execution of the first expression 
exp2: determining whether an execution condition of the loop body 
exp3: increment operations do

By the end of the break for loop

for(var i=1;i<=100;i++){
if(i>100){
break;//结束for循环 
  }
document。write(i+'/<br/>');
}

continue: means skip the current cycle, enter the next cycle.

for( var i=1; i<=10;i++){
if (i==3){
document.write(i+'hello');
continue;
}
document.write(i+'<br/>')
}

for the nested loop

for ( var I =. 1; I <=. 3; I ++ ) { 
document.write ( 'outer loop of the' + i 'results herein <br />' );
 for ( var J =. 1; J <= 2; ++ J ) { 
document.write ( 'inner loop of the' + i 'results herein <br/>' ); 
} 
Document. Write ( '<HR />' ); 
}

Conditional statements:

if the conditional statement

IF (. 3>. 11 ) 
document.write ( 'Hello' ); 
document.write ( 'of hello2' );
 // this wording is correct, when the condition that triggered the first, if not satisfied, the trigger surprised

if ( to false ) { 
document.write ( 'Hello' ) 
document.write ( 'King' )
 var X =. 1, Y = 2, username = 'King' 
} 
// when if there is false, var judged only , x, y, username type rather than judgment value.

<scrip>


var username = 'King' ;
             IF (username == 'King' ) { 
                document.write ( 'Hello King' ); 
            } the else { 
                document.write ( 'Hello Nana' ); 
            } 
// when the operation time, outputs ' Hello Nana', since the inside js, represents a length of a space point, 
so the 'king' and 'king' is not the same.

</scrip>

switch ... case statement

Calculated once the switch expression
The value of the expression is compared with the value for each case of
If there is a match, then the association code execution

<Scrip> 
 Switch (exp) {
                  Case Value 1: 
                     code segments executed; 
                     BREAK ;
                  Case Value 2: 
                     code segments executed; 
                     BREAK ; 
                 ... 
                 default : 
                     code segments executed; 
                     BREAK ; 
                 more stringent type 
             }

</scrip>

while loop: Calcd expression, when the value is true (non-zero), the loop statement is executed.

the while (loop condition) { 
cycle theme; 
}

do ... while loop: The difference and while do-while loop is that: it is the first execution of the loop statement, and then determine whether the expression is true, if the loop continues is true; if false, is terminated cycle. Therefore, do-while loop to execute at least one loop.

JavaScript conditional statement

if statement: If the condition is true for a predetermined sj is a block of code to be executed

else statement: The original provision was added condition is false the new conditions

else if statement: originally specified when the new condition is flase first condition

The switch statement: perform different actions for different conditions

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