Chapter 5: Relational Operators in JavaScript

　

　

5.1 Relational Operators

In chapter 4, we have learned basic arithmetic operations in JavaScript, this chapter will introduce the more powerful relational operators. Using relational operators, we could write decision making procedures using If keyword.

Relational Operators Meaning
x==y
x is equal to y
x!=y
x is not equal to y
x>y
x is more than y
x<y
x is less than y
x>=y

x is more than or equal to y
x<=y

x is less than or equal to y

　

Example: 

　

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>

<HEAD>
<TITLE>Using Comparison Operators </TITLE>

<SCRIPT LANGUAGE = "JavaScript">
var      firstNumber, //declare first variable
          secondNumber; //declare second variable


firstNumber = window.prompt( "Enter first Number:", "0" );

secondNumber = window.prompt( "Enter second integer:", "0" );

document.writeln( "<H1>Comparison Output</H1>" );
document.writeln( "<TABLE BORDER = '1' WIDTH = '100%'>" ); // Creates table

if ( first == second )
document.writeln( "<TR><TD>" + firstNumber + " = " + secondNumber  +
"</TD></TR>" );    // Creates rows and columns

if ( first != second )
document.writeln( "<TR><TD>" + firstNumber  + " Not equal to " + secondNumber  +
"</TD></TR>" );

if ( first < second )
document.writeln( "<TR><TD>" + firstNumber  + " < " + secondNumber  +
"</TD></TR>" );

if ( first > second )
document.writeln( "<TR><TD>" + firstNumber  + " > " + secondNumber  +
"</TD></TR>" );

if ( first <= second )
document.writeln( "<TR><TD>" + firstNumber  + " <= " + secondNumber  +
"</TD></TR>" );

if ( first >= second )
document.writeln( "<TR><TD>" + firstNumber + " >= " + secondNumber  +
"</TD></TR>" );

// Display results
document.writeln( "</TABLE>" );
</SCRIPT>

</HEAD>
<BODY>
<P>Click Refresh (or Reload) to run the script again</P>
</BODY>
</HTML>

　

Click Testing Page to view the output
　

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