JavaScript | Statements
The programming instructions written in a program in a programming language are known as statements.
Order of execution of Statements is the same as they are written.
- Semicolons:
- Semicolons separate JavaScript statements.
- Semicolon marks the end of a statement in javascript.
Example:
<!DOCTYPE html>
<
html
>
<
body
>
<
h2
>Welcome</
h2
>
<
p
id
=
"geek"
></
p
>
<
script
>
// Statement 1
var a, b, c;
// Statement 2
a = 2;
// Statement 3
b = 3;
// Statement 4
c = a + b;
document.getElementById(
"geek").innerHTML =
"The value of c is " + c + ".";
</
script
>
</
body
>
</
html
>
Output:
- Multiple statements on one line are allowed if they are separated with a semicolon.
a=2;b=3;z=a+b;
- Code Blocks:
JavaScript statements can be grouped together inside curly brackets. Such groups are known as code blocks. The purpose of grouping is to define statements to be executed together.Example:JavaScript function
<!DOCTYPE html>
<
html
>
<
body
>
<
p
>Welcome</
p
>
<
button
type
=
"button"
onclick
=
"myFunction()"
>
Click Me!
</
button
>
<
p
id
=
"geek1"
></
p
>
<
p
id
=
"geek2"
></
p
>
<
script
>
function myFunction() {
document.getElementById(
"geek1").innerHTML = "Hello";
document.getElementById(
"geek2").innerHTML =
"How are you?";
}
</
script
>
</
body
>
</
html
>
Output:
Before Click:
After Click: - White Space:
- Javascript ignores multiple white spaces.
Javascript would treat following 2 statements as same:
Example:var a="Hello Geek"; var a = "Hello Geek";
- Line Length and Line Breaks:
Javascript code preferred line length by most programmers is upto 80 characters.
The best place to break a code line in Javascript, if it doesn’t fits, is after an operator.
Example:document.getElementById("geek1").innerHTML = "Hello Geek!";
- Keywords:
Keywords are reserved words and cannot be used as variable name.
A Javascript keyword tells about what kind of operation it will perform.Some commonly used keywords are:
- break: This is used to terminate a loop or switch.
- continue: This is used to skip a particular iteration in a loop and move to next iteration.
- do…. while: In this the statements written within do block are executed till the condition in while is true.
- for: It helps in executing a block of statements till the condition is true.
- function: This keyword is used to declare a function.
- return: This keyword is used to exit a function.
- var: This keyword is used to declare a variable.
- switch: This helps in executing a block of codes depending on different cases.