Page 47 - trackpad v5.1 class 8 flipbook
P. 47

When the preceding statement is executed, a prompt box will appear in the web browser asking
                 to input the age. By default, the input taken by the prompt( ) method is considered as a string in
                 JavaScript.
                 If you want to perform mathematical calculations, you need to convert the value into an integer
                 by using the parseInt( ) method and into a floating-point number by using the parseFloat( )
                 method. We can use the parseInt( ) method in the following way:

                 var num = parseInt(prompt("Enter first number: "));
                 The document.write( ) method is used to display output on the web page.
                 For example:

                 document.write("Hello from JavaScript");
                 The preceding statement will display the message "Hello from JavaScript" on the web page. Let us
                 create a web page to calculate the sum of two numbers in JavaScript.

                 <HTML>
                 <HEAD>
                 <TITLE> Statements in JavaScript </TITLE>
                 </HEAD>
                 <BODY>
                 <SCRIPT type="text/javascript">
                 var a = parseInt(prompt("Enter first number: "));
                 var b = parseInt(prompt("Enter second number: "));
                 var c;
                 c = a + b;
                 document.write("The sum is: ");
                 document.write(c);
                 </SCRIPT>
                 </BODY>
                 </HTML>
                 Save the file with .html extension and open the web page in web browser. You will get the following
                 output:




























                                                                                      Dynamic Web Pages in HTML5  45
   42   43   44   45   46   47   48   49   50   51   52