JavaScript

www.SunilOS.com 1
www.sunilos.com
www.raystec.com
JavaScript

Hello.html
<HTML>
<HEAD></HEAD>
<BODY>
<center><b><u>
Hello
</u></b></center>
</BODY>
</HTML>
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Submit Data From HTML Form
<HTML>
<HEAD></HEAD>
<BODY>
<FORM METHOD=“GET” ACTION="HelloName.jsp">
Enter Name
<INPUT TYPE="text" NAME="fName">
<INPUT VALUE="GO" TYPE="submit">
</FORM>
</BODY>
</HTML>
GET
POST
On Submit -
http://localhost:8080/aajkiapp/HelloName.jsp?fName=Sunrays
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FORM Fields
 <FORM METHOD=GET ACTION="">
 Text Field<INPUT TYPE="text" NAME="userId"><BR>
 Password Field<INPUT TYPE="password" NAME ="pwd"><BR>
 Checkbox Field<INPUT TYPE="checkbox" NAME="checkBox"
VALUE="1" ><BR>
 Radio Field<INPUT TYPE="radio" NAME="degree" VALUE="MCA">
 <INPUT TYPE="radio" NAME="degree" VALUE="BE"><BR>
 Button <INPUT TYPE="button" NAME="action" VALUE="Go"><BR>
 Submit Button<INPUT TYPE="Submit" VALUE="Submit"><BR>
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FORM Fields (Cont.)
 Reset Button<INPUT TYPE="reset" VALUE="Clear"><BR>
 TextArea<TEXTAREA NAME="tArea" ROWS="2"
COLS="20"></TEXTAREA><BR>
 List <SELECT NAME="list">
 <OPTION VALUE="1">ONE</OPTION>
 <OPTION VALUE="2">TWO</OPTION>
 </SELECT><BR>
 Hidden Value<INPUT TYPE="hidden" NAME="id"
VALUE="123">
 </FORM>
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JavaScript
It is the scripting language of the Web.
It is used in millions of Web pages to add
functionalities:
o Validate forms
o Detect browsers
o Handle Cookies
..and much more
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Key points
 Javascript functions are written in script tag.
o <script language="text/javascript">…</script>
 Tag <script > can be written anywhere in HTML but
<HEAD> tag is preferred to write it because head position
is first loaded in browser.
 Function is always started with 'function' key word.
 Variables are defined by optional 'var' keyword. For
example
o var msg =0; //with var
o OR
o msg=0; //witout var
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Key points (Cont.)
 Data type of a variable is depending on its stored
value.
o var num= 1; //integer
o var name ="sunrays“; //string
o var salary = 1.5; //float
 String can be represented by single quote (') or
double quote (") in Javascript.
o var org = “sunrays”;
o var org = 'sunrays' ;
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<INPUT event
Attribute The event occurs when...
onabort Loading of an image is interrupted
onblur An element loses focus
onchange The user changes the content of a field
onclick Mouse clicks an object
ondblclick Mouse double-clicks an object
onerror An error occurs when loading a document or an image
onfocus An element gets focus
onkeydown A keyboard key is pressed
onkeypress A keyboard key is pressed or held down
onkeyup A keyboard key is released
onload A page or an image is finished loading
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Javascript Objects
 <HTML>
 <HEAD></HEAD>
 <BODY>
 <FORM NAME=‘helloForm’ METHOD=“GET”
ACTION="HelloName.jsp">
o Enter Name
o <INPUT TYPE="text" NAME=“name“ VALUE=‘XYZ’>
 <INPUT VALUE="GO" TYPE="submit">
 </FORM>
 </BODY>
 </HTML>
document
form
name
alert(document.helloForm.name.value);
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Confirm Box (Are You Sure) ?
<form action="Abc.jsp">
Roll NO <input type="text" name="rollNo">
<input name="operation" type="button"
value="Delete“ onclick="doDelete(this.form)" >
</form>
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Confirm Box ( Cont.)
 <script type="text/javascript">
 function doDelete(frm){

 if(frm.rollNo.value == ''){
 alert("Roll number can not be null")
 frm.rollNo.focus();
 }else {
 var flag = confirm("Are you sure ?");
 if(flag){
 frm.submit();
 }
 }
 }
 </script>
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Sum of two Numbers
 <form name=“calForm” >
 <input type="text" name="num1">+
 <input type="text" name="num2">=
 <input type="text" name="sum" readonly=“true">
 <input type="button" value="Calculate" onclick="calc(document.calForm)"
>
 <input type="button" value="Calculate“ onclick="calc(this.form)" >
 </form>
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Sum of two Numbers
 <form action="">
 <input type="text" name="num1“ onchange="calc(this.form)" >
 + <input type="text" name="num2“ onchange="calc(this.form)" >
 = <input type="text" name="sum" readonly=“true">
 <input type="button" value="Calculate" onclick="calc(this.form)" >
 </form>
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Calculate Sum
<script type="text/javascript">
function calc(frm){
 var n1 = parseInt(frm.num1.value);
 var n2 = parseInt(frm.num2.value);
 frm.sum.value = n1 + n2;
 return frm.sum.value;
}
</script>
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Validation on form submit
<form onsubmit="return validate(this)">
o User ID <input type="text" name="id"><br>
o Password <input type=“text" name="pwd">
o <input type="submit" value=“Go" >
</form>
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Validate method
 function validate(frm){

 var flag = true;
 if(frm.id.value == ''){
 alert("User ID can not be null");
 flag = false;
 }
 if(frm.pwd.value == ''){
 alert("Password can not be null");
 flag = false;
 }
 return flag;
 }
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Reusable functions .js file
Reusable functions can be stored in a text file that
has extension .js.
HTML pages can import functions from a .js file to
use them.
HTML pages can import multiple .js files.
Include .js files into HTML by <script> tag:
o <script type="text/javascript" src="menu.js">
o <script type="text/javascript" src=“calendar.js">
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Javascript Frameworks
JQuery
Angular JS
Ext JS
Prototype
DOJO
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AJAX
 Asynchronous JavaScript and XML
 HTML pages call a web resource (web page)
asynchronously (in the background) without impacting
existing displaying page.
 HTML pages can send and receive data with the help of
AJAX from the source server asynchronously.
 Object XMLHttpRequest is used to make asynchronous
calls.
 Usually JSON data fetched by AJAX calls.
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Get XmlHttpObject
 function getXmlHttpObject(){
 var xmlHttp=null;
 try{
 // Firefox, Opera 8.0+, Safari
 xmlHttp=new XMLHttpRequest();
 }
 catch (e){
 // Internet Explorer
 try{
 xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
 }
 catch (e){
 xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
 }
 }
 return xmlHttp;
 }
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HTML
 Sign Up Guest :
 <INPUT TYPE="radio“ NAME="site“ onClick="getContent(‘/App/Guest')">
 Sign Up Patient:
 <INPUT TYPE="radio" NAME="site“ onClick="getContent('/App/Patient')">
 Sign Up Doctor:
 <INPUT TYPE="radio" NAME="site“ onClick="getContent('/App/Doctor')" >
 <TD id='bodyText'> AJAX Text will be replaced here </TD>
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Get Data
 function getContent(url){
o var xmlHttp = getXmlHttpObject();
o xmlHttp.open("GET",url,true);
o //attach function
o xmlHttp.onreadystatechange=function(){
 if(xmlHttp.readyState==4 && xmlHttp.status == 200) {
• var cont = xmlHttp.responseText;
• document.getElementById('bodyText').innerHTML = cont;
 }
o }
o xmlHttp.send(null);
 }
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Disclaimer
This is an educational presentation to enhance the
skill of computer science students.
This presentation is available for free to computer
science students.
Some internet images from different URLs are
used in this presentation to simplify technical
examples and correlate examples with the real
world.
We are grateful to owners of these URLs and
pictures.
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Thank You!
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www.SunilOS.com

JavaScript

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