The label in JavaScript is used in conjunction with break

Grammar

label:    statement

Description

The label statement can add tags to the code for future use. The defined label can be referenced in the future by a break or continue statement. Tagged statements are generally used in conjunction with loop statements such as for statements.

// 示例let count = 0;loop1:for (let i = 0; i < 10; ++i) {    for (let j = 0; j < 10; ++j) {        if (i === 6 && j === 6) {            break loop1;        }        ++count;    }}console.log(count); // 66

Normally, break exits only the nearest loop, and the above example returns 96. But the tag loop marks the outermost for loop, so it exits the entire loop after break.

You can also have multiple tags within a loop.

// 示例let count = 0;loop1:for (let i = 0; i < 10; ++i) {    loop2:    for (let j = 0; j < 10; ++j) {        for (let k = 0; k < 10; ++k) {            if (i === 6 && j === 6 && k === 6) {                break loop2;            }            ++count;        }    }}console.log(count); // 966

The label in JavaScript is used in conjunction with break