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Output of the preceding program is as follows:
                 Hello, Alice!! hello
                 Types of Functions

                 There are several types of functions in JavaScript,  each serving different purposes and offering various
                 syntactic styles.

                 Built-in functions

                 Built-in  functions  in  JavaScript  are  ready-made  functions  provided  by  the  language.  They  help  perform
                 common tasks such as converting data types, handling strings, or working with numbers, making coding
                 faster and more efficient.
                 Some built-in functions are as follows:
                   parseInt( ): Built-in function to convert to an integer.

                   parseFloat( ): Built-in function to convert to a floating-point number.
                   isNaN( ): Built-in function to check if something is Not a Number. For a number it returns False, otherwise
                    it returns true.
                   alert(“message”): If you want to make sure that information reaches the user, an alert box is commonly
                    utilised.
                   confirm(“message”): If you want the user to verify or accept information, a confirm box is frequently
                    utilised.

                   prompt(“message”): If you want the user to enter a value before seeing a page, a prompt box is frequently
                    utilised.
                 Example 11: To demonstrate the use of parseInt, parseFloat, and isNaN function

                    <!DOCTYPE HTML>

                    <HTML>
                    <HEAD>
                    <TITLE>JavaScript Built-in Functions Example</TITLE>
                    </HEAD>

                    <BODY>
                    <H2>JavaScript Built-in Functions Demo</H2>
                    <SCRIPT>
                    // Using parseInt()
                    var intNumber = parseInt("42");
                    document.writeln("parseInt('42'): " + intNumber+"<BR>");

                    document.writeln("  Type: " + typeof intNumber + "<BR><BR>");
                    // Using parseFloat()
                    var floatNumber = parseFloat("3.14");
                    document.writeln("parseFloat('3.14'): " + floatNumber+"<BR>");
                    document.writeln("  Type: " + typeof floatNumber + "<BR><BR>");
                    // Using isNaN()

                    var checkNaN1 = isNaN("Hello");

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