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.

  1. Semicolons:
    • Semicolons separate JavaScript statements.
    • Semicolon marks the end of a statement in javascript.

      Example:

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      <!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>

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      Output:
      
Image

      • 

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

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

      • 

    

    2. 

  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


    

    

    

    

    

    
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    <!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> 
    

    
    		

    
    

    

    

    

    

    

    
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    Output:
    
Before Click:
    
Image
    
After Click:
    
Image

    3. 

  3. White Space:

      

    • Javascript ignores multiple white spaces. 
      • 

    

     Javascript would treat following 2 statements as same:
    
Example:
    

    var a="Hello Geek";
var a = "Hello Geek";

    

    4. 

  4. 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!";

    

    5. 

  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: 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. 
      • 

    

    6. 



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