The purpose of a while loop is to execute a statement or code block repeatedly as long as an expression is true. Once the expression becomes false, the loop terminates.
Example
You can try to run the following code to learn how to use nested while loop
Live Demo
<html>
<body>
<script>
var height = 2;
var width = 8;
var col = 0;
var row = 0;
document.write("Starting Loop<br> ");
while (row < height) {
col = 0;
while(col < width) {
document.write("#");
col++;
}
document.write("<br>");
row++;
}
document.write("Loop stopped!");
</script>
</body>
</html>