JavaScript Statements

The programming instructions written in a program in a programming language are known as statements. The order of execution of Statements is the same as they are written.

1. Semicolons:

• Semicolons separate JavaScript statements.
• A semicolon marks the end of a statement in javascript. 

Example:

html

<h2>Welcome</h2>
<p id="geek"></p>
<script>
    var a, b, c;
    a = 2;
    b = 3;
    c = a + b;
    document.getElementById("geek")
              .innerHTML =
              "The value of c is " + c + ".";
</script>

• Output:

• Multiple statements on one line are allowed if they are separated with a semicolon.

a=2;b=3;z=a+b;

2. 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 

html

<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>

Output:

3. White Space:

• Javascript ignores multiple white spaces.

4. Line Length and Line Breaks: Javascript code preferred line length by most programmers is up to 80 characters. The best place to break a code line in Javascript, if it doesn’t fit, is after an operator. 

Example:

document.getElementById("geek1").innerHTML =
"Hello Geek!";

5. 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 and continue: break keyword is used to terminate a loop and continue 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.
• switch: This helps in executing a block of codes depending on different cases.
• var, let  and const : These keywords are used to declare a variable in js.