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.

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Which attribute specifies the HTTP method (GET, POST) used to submit the form-data?
action method value
<form action="script.php" method="post"> ... </form>
Which CSS property allows to add shadow to boxes?
background-image box-shadow border-radius
#id {
  background-color: #bbfeda;
  box-shadow: 11px 11px 5px #7878da;
}
Which function removes the first element from an array?
pop() push() shift()
var fruits = ["apple", "apricot", "banana"];
fruits.shift();
alert(fruits.length);           // 2
Indicate the function that can be used to check if a PHP extension is instaled.
function() filetype() extension_loaded()
if(extension_loaded("PDO") === true) echo "PDO is available."
While loops

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