Loops in JavaScript


The for loop

for (var = 1; var < 10; var++) { ... }

The while loop

while (total < 10) {
	n++;
	total += values[n];
}

do {
	n++;
	total += values[n];
} while (total < 10);

An infinite loop

while (true) { ... }

Breaking out of a loop

while (true) {
	n++;
	if (values[n] == 1) break;
}

Continuing a loop

for (i = 1; i < 21; i++) {
	if (score[i] == 0) continue;
	document.write ("Student number ", i, " Score : ", score[i], "\n");
}

The for ... in loop

for (i in navigator) {
	document.write ("property: " + i);
	document.write (" value: " + navigator[i]);
}

Arrays & loops

names = new Array();
i = 0;

do {
	next = window.prompt ("Enter the Next Name");
	if (next > " ") names[i] = next;
	i = i + 1;
} while (next > " ");

Generating HTML dynamically

document.write ("<OL>");
for (i in names) {
	document.write ("<LI>" + names[i] + "<BR>");
}
document.write ("<OL>");

Generating HTML dynamically (Prompt for names and display them)

...

names = new Array();
i = 0;

do {
	next = window.prompt ("Enter the Next Name");
	if (next > " " && next != "undefined") names[i] = next;
	i = i + 1;
} while (next > " " && next != "undefined");

document.write ("<H3>" + (names.length) + " names entered.</H3>");
document.write ("<OL>");
for (i in names) {
	document.write ("<LI>" + names[i] + "<BR>");
}
document.write ("</OL>");

...
Run the Script above.