Break and Continue

Sometimes we want to exit a loop or do the next loop iteration early, to do so we use the break; and continue; statements respectively.

break [label];

Exits the loop immediately. Execution continues at the point following the loop.

The optional label is used to break from a nested loop or from within a switch statement within a loop.

Examples:

var i = 0, s = "A string with more than 10 characters"; while (true) { console.log(i, s[i]); if (i++ > 8) break; }

Prints the first 10 letters of the string in s with its index number and stops.

continue [label];

Immediately goes to the expression test part of the loop, skipping any remaining statements in the loop.

/** * s = The string to scan. * i = Index into the string s; * t = A new string which will hold s minus the vowels. */ var i=0, c, s = "The quick brown fox jumped over the fence."; var t = ""; // Set c to the character in s at index i. If s[i] is null this will stop // the loop since the result of the assignment is not true. while ((c = s[i++]) !== undefined) { if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') continue; // Not a vowel, so append the character in c to t: t += c; } // Will print what was in s but w/o any vowels: console.log(t);