JavaScript Tutorial JavaScript References

JavaScript - Label Statement



The label statement is used with break or continue statements. It is used to prefix a statement with an identifier which can be referred. A label can be specified by any name other than the reserved words in JavaScript. The syntax for using label is given below:

Syntax

label :
  statements;

Label statement with Continue statement

A label is used to identify a loop, and then continue statement is used to indicate when to skip the current iteration.

var txt = "";

loop1 :
for (i = 1; i <= 5; i++){
  if(i == 3)
    continue loop1;
  txt = txt + "i = " + i + "<br>";
}

The output (value of txt) after running above script will be:

i = 1
i = 2
i = 4
i = 5

In the example below, label statement is used to skip the inner and outer loop respectively whenever the conditions are met.

var txt ="#Skips the inner loop<br>";

loop1 :
for (i = 1; i <= 3; i++){
  loop2 :
  for (j = 1; j <= 3; j++){
    if(i == 2 && j == 2)
      continue loop2; 
    txt = txt + "i = " + i + ", j = " + j +"<br>"; 
  }
}

txt = txt + "<br>#Skips the outer loop<br>";
loop3 :
for (i = 1; i <= 3; i++){
  loop4 :
  for (j = 1; j <= 3; j++){
    if(i == 2 && j == 2)
      continue loop3; 
    txt = txt + "i = " + i + ", j = " + j +"<br>"; 
  }
}

The output (value of txt) after running above script will be:

#Skips the inner loop
i = 1, j = 1
i = 1, j = 2
i = 1, j = 3
i = 2, j = 1
i = 2, j = 3
i = 3, j = 1
i = 3, j = 2
i = 3, j = 3

#Skips the outer loop
i = 1, j = 1
i = 1, j = 2
i = 1, j = 3
i = 2, j = 1
i = 3, j = 1
i = 3, j = 2
i = 3, j = 3

Label statement with Break statement

A label is used to identify a loop, and then break statement is used to indicate when to get out of the loop.

var txt = "";

loop1 :
for (i = 1; i <= 5; i++){
  if(i == 3)
    break loop1;
  txt = txt + "i = " + i + "<br>";
}

The output (value of txt) after running above script will be:

i = 1
i = 2

In the example below, label statement is used to skip the inner and outer loop respectively whenever the conditions are met.

var txt ="#Breaks from the inner loop<br>";

loop1 :
for (i = 1; i <= 3; i++){
  loop2 :
  for (j = 1; j <= 3; j++){
    if(i == 2 && j == 2)
      break loop2; 
    txt = txt + "i = " + i + ", j = " + j +"<br>"; 
  }
}

txt = txt + "<br>#Breaks from the outer loop<br>";
loop3 :
for (i = 1; i <= 3; i++){
  loop4 :
  for (j = 1; j <= 3; j++){
    if(i == 2 && j == 2)
      break loop3; 
    txt = txt + "i = " + i + ", j = " + j +"<br>"; 
  }
}

The output (value of txt) after running above script will be:

#Breaks from the inner loop
i = 1, j = 1
i = 1, j = 2
i = 1, j = 3
i = 2, j = 1
i = 3, j = 1
i = 3, j = 2
i = 3, j = 3

#Breaks from the outer loop
i = 1, j = 1
i = 1, j = 2
i = 1, j = 3
i = 2, j = 1

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