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JavaScript Statements- Looping
JavaScript Statements enable you to implement logic, looping, and more within your script.
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Looping Statements
Statements | Description |
---|---|
for | Probably the most common looping
statement, "for " executes the enclosed statements
multiple times based on the 3 conditions an initial, limit, and
increment condition) defined inside the
for(...) parenthesis.Syntax: for (initialValue; test; increment) Example: for (var x=0; x<3; x++){
You can define more than 1 expression for either the initial or
increment conditions the
for (var x=0, y=3; x<5;
x++, y=x*3){ |
while | A while loop continuously executes the
enclosed statements as long as the tested expression evaluates to
true. If the expression is false to begin with, the entire while
loop is skipped. Syntax: while (expression) Example: var number=0 |
do/while | The do/while statement differs from the
standard "while" in that the expression tested for is put at the
end, ensuring that a do/while loop is always executed at least
once.. Syntax: do Example: var number=0 |
for/in | For/in is a special looping statement
that lets you loop through the properties of an object, either built
in or custom objects. Syntax: for (var prop in object) where " For built in objects, Here are two examples. Example 1: This example writes out all the properties of
the " for (var myprop in navigator){ Output: Example 2: This example loops through all properties within a custom object: var userprofile={name:'George', age:30,
sex:'male', getage:function(){return this.age}} Output: Notice how the method |
break | The break statement causes an exit of
the innermost loop the statement is contained in. It's useful to
prematurely end a loop: Example: for (i=0; i<6;
i++){ |
continue | The continue statement causes
JavaScript to skip the rest of the statements that may follow in a
loop, and continue with the next iteration. The loop is not
exited, unlike in a break statement. Example: for (i=1; i<6;
i++){ |
- JavaScript Operators
- JavaScript Statements
- Global functions
- JavaScript Events
- Escape Sequences
- Reserved Words