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Java Scripting Part2-Information Technology-Lecture Handout, Exercises of Information Technology
Main tpoics for the course are mentioned here. What is E-Commerce and its type. Networking Devices. Markup languages. Security issues. Data mining. E-business. Cryptography and public key infrastructure. Electronic Data Exchange. Internet marketing. ERP. This lecture includes: Java, Scripting, Addition, Subtraction, Document, Object, Modification, Html, Script, Language, Function
Typology: Exercises
2011/2012
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Download Java Scripting Part2-Information Technology-Lecture Handout and more Exercises Information Technology in PDF only on Docsity! E-COMMERCE – IT430 VU © Copyright Virtual University of Pakistan 61 Lesson 14 JAVA SCRIPTING (CONTINUED….) We can also get the result of addition or subtraction written on a page using ‘write’ function of the document object. Again we need to do a slight modification in the code as shown below. <HTML> <script language="JavaScript"> <!-- function Addit() { var num1=document.Calform.One.value; var num2=document.Calform.Two.value; document.write("The result of this addition is " + (parseFloat(num1)+parseFloat(num2))); } function minus() { var num1=document.Calform.One.value; var num2=document.Calform.Two.value; document.write("The result of this subtraction is " + (parseFloat(num1) parseFloat(num2))); } //--> </script> <BODY> <FORM name="Calform"> <P> First Number:<INPUT TYPE="TEXT" NAME="One" maxlength="3"> <P> Second Number:<INPUT TYPE="TEXT" NAME="Two" maxlength="3"> <P> <INPUT TYPE="button" NAME="Add" VALUE="Add Them!!" onclick="Addit()"> <INPUT TYPE="button" NAME="Minus" VALUE="Subtract Them!!" onclick="minus()"> <INPUT TYPE="RESET" VALUE="Reset!"> </FORM> </BODY> </HTML> When a user types 3 and 9 in the two text boxes, respectively, as shown in Fig. 1 below and presses ‘AddThem!!’ the addition of two nos. ‘12’ is written on a web page (Fig. 2). On clicking ‘Subtract Them!!’ the subtraction of two nos. ‘-6’ is written on a page (Fig. 3). Note that in the brackets of ‘document.write’ we concatenate or join some text information called string (within double quotation marks) with the addition/subtraction of two nos. using ‘+’ sign. The addition/subtraction of nos. is achieved using function ‘parseFloat()’, that is, a function of predefined global object. docsity.com E-COMMERCE – IT430 VU © Copyright Virtual University of Pakistan 62 Fig. 1 Fig. 2 Fig. 3 Multiply and divide calculator See the following code: <HTML> <script language="JavaScript"> <!-- function Multiplyit() { var num1=document.Calform.One.value; var num2=document.Calform.Two.value; alert(parseFloat(num1)*parseFloat(num2)); } function Divideit() { var num1=document.Calform.One.value; var num2=document.Calform.Two.value; alert(parseFloat(num1)/parseFloat(num2)); } //--> </script> <BODY><h2> Multiply and Divide Calculator</h2> <FORM name="Calform"> <P> First Number:<INPUT TYPE="TEXT" NAME="One" maxlength="3"> <P> Second Number:<INPUT TYPE="TEXT" NAME="Two" maxlength="3"> docsity.com E-COMMERCE – IT430 VU © Copyright Virtual University of Pakistan 65 Example - If Statement IF statement in programming is used to alter the course of execution of code depending upon the value of a condition. See the following example: <HTML> <script language="JavaScript"> <!-- function minus() { var num1=document.Calform.One.value; var num2=document.Calform.Two.value; if(parseFloat(num1)<parseFloat(num2)) { alert("negative"); } else { alert(parseFloat(num1)-parseFloat(num2)); } } //--> </script> <BODY> <FORM name="Calform"> <P> First Number:<INPUT TYPE="TEXT" NAME="One" maxlength="3"> <P> Second Number:<INPUT TYPE="TEXT" NAME="Two" maxlength="3"> <P> <INPUT TYPE="button" NAME="Minus" VALUE="Subtract" onclick="minus()"> <INPUT TYPE="RESET" VALUE="Reset!"> </FORM> </BODY> </HTML> Results are shown in Figures 7 and 8 below. Fig. 7 docsity.com E-COMMERCE – IT430 VU © Copyright Virtual University of Pakistan 66 Fig. 8 For LOOP When we want some action to take place repeatedly till a particular point, we can apply a for loop. General format is: for(initializationStatement;condition;updateStatement){statements}. The code goes on executing itself till a certain condition is met. Example <HTML> <HEAD> <TITLE>Using the For Statement</TITLE> </HEAD> <BODY> <SCRIPT> <!-- for(i=1;i<7;i++) document.write("<H"+i+">Hello "+i+"!!</H"+i+">"); //-> </SCRIPT> </BODY> </HTML> Result is shown in Fig. 9 below. Fig. 9 docsity.com E-COMMERCE – IT430 VU © Copyright Virtual University of Pakistan 67 Note that using for loop we are able to generate six different levels of headings in HTML. Some predefined JavaScript objects A list of some commonly used predefined JavaScript object is given below: Global Array String Math Date Global object is an object with globally-accessible variables/properties and functions. Netscape navigator and internet explorer implement Global object, but do not allow it to be explicitly created or referenced. Instead its properties and methods are referenced directly. NaN - ‘not a number’ is one of its properties. ‘parseFloat(string)’ that parses the string as a floating point number, is the example of a function/method of Global Object. Note a general difference between properties and functions of an object in that the names of the properties are not followed by small brackets whereas the names of the functions do have small brackets following their names. Information contained in the small brackets of a function is called arguments. Also note that generally properties and functions of an object are invoked/referenced by typing the name of the object followed by a dot before typing the property or function name, e.g, document.write(). Array Object also has different properties and functions. ‘Length’ is an important property of this object that identifies the length of the array. Its methods/functions include toString(), reverse(), sort() etc. Array Example <HTML> <HEAD> <TITLE>Using Arrays </TITLE> </HEAD> <BODY> <H1>Using Arrays </H1> <SCRIPT LANGUAGE="JavaScript" TYPE="text/javascript"> <!-- myArray=[0,1,2,3,4,5,6,7,8,9,10]; document.write("myArray: first element " +myArray[0]+"<P>"); document.write("myArray.toString(): "+myArray.toString()+"<P>"); document.write("myArray.join(':'): "+myArray.join(':')+"<P>"); document.write("myArray.reverse(): "+myArray.reverse()+"<P>"); document.write("myArray.sort(): "+myArray.sort()+"<P>"); //--> </SCRIPT> </BODY> </HTML> Result is shown in Fig. 10 below. Fig. 10 docsity.com
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