A
while loop just looks at a short comparison and repeats until the comparison is no longer True.
The while() loop
The while() loops executes a code as long as a condition is True. If the condition starts out as false, the statements won’t execute at all.
- Syntax:
while(condition){
//code to be executed
}
Example:
<script>
var i =0;
while(i<5){
document.write('<br /> i = '+i);
i++;
}
</script>
- First it's declared a variable 'i' with the value of 0. The 'while' statement checks the condition (here: i<5), which it's True and permits the execution of block code inside the brackets. The 'i++' increments the value of 'i' and check again the condition. The loop will stop when the 'i' reach 5.
do ... while() loops
The do...while() loop is a variant of the while() loop. First it is executed the block of code, and then it will repeat the loop as long as the specified condition is true.
Syntax:
do {
//code to be executed
}
while(condition)
Here is a simple example:
<script>
var x = 8;
do {
document.write('<br> x = '+x);
x++;
}
while(x<5)
</script>
- This example display 'x = 8'.
As you can notice, although the condition is false (x<5), the code between braces is still executed once.
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