A brief discussion of Label statements in Javascript

Label statement, according to the syntax in the book is:

Label: statement

如： begin: for (var i = 0; i < 10 ; i++ ){
     alert(i);
   }

For a typical example, see After finishing, you will understand the application of Label: (No Label added)

var num = 0;
 for (var i = 0 ; i < 10 ; i++){
   for (var j = 0 ; j < 10 ; j++){
    if( i == 5 && j == 5 ){
     break;
    }
   num++;
   }
 }

alert(num); // The loop will jump out of the j loop when i is 5 and j is 5, but it will continue to execute the i loop and output 95

Comparison of the program after using Label: (after adding Label)

var num = 0;
outPoint:
for (var i = 0 ; i < 10 ; i++){
  for (var j = 0 ; j < 10 ; j++){
   if( i == 5 && j == 5 ){
    break outPoint;
   }
  num++;
  }
}
alert(num); // 循环在 i 为5，j 为5的时候跳出双循环，返回到outPoint层继续执行，输出 55

Compare the use of break and continue statements:

var num = 0;
　　outPoint:
　　for(var i = 0; i < 10; i++)
　　{
 　　for(var j = 0; j < 10; j++)
 　　{
  　　if(i == 5 && j == 5)
  　　{
   　　continue outPoint;
  　　 }
  　　 num++;
 　　}
　　}
　　alert(num); //95

As can be seen from the value of alert(num), the function of the continue outPoint; statement is to jump out of the current loop and jump to outPoint ( The for loop under the label) continues to execute.

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