JavaScript

Sticky session refers to the feature of many commercial load balancing solutions for web-farms to route the requests for a particular session to the same physical machine that serviced the first request for that session. This is mainly used to ensure that a in-proc session is not lost as a result of requests for a session being routed to different servers. Since requests for a user are always routed to the same machine that first served the request for that session, sticky sessions can cause uneven load distribution across servers.

The most common reason for this error is that the the machine key value in machine.config is different for each server. As a result, view state encoded by one machine cannot be decoded by another. To rectify this, edit the machine.config file on each server in the web-farm to have the same value for machine key.

Undefined value means the variable used in the code doesn't exist or is not assigned any value or the property doesn't exist

(i) Undefined value cannot be explicitly stated that is there is no keyword called undefined whereas null value has keyword called null

(ii) typeof undefined variable or property returns undefined whereas typeof null value returns object

It is perfectly legal to assign a number to a variable and then assign a string to the same variable as follows

example

i = 10;

i = "string";

This is called variable typing

No. Javascript does not have block level scope, all the variables declared inside a function possess the same level of scope unlike c, c++, java.

//select all input tags

function SelectAll() {

var checkboxes = document.getElementsByTagName("input");

for(i=0;i<checkboxes.length;i++) {

if(checkboxes.item(i).attributes["type"].value == "checkbox") {

checkboxes.item(i).checked = true;

}

}

}

Undeclared variables are those that are not declared in the program (do not exist at all), trying to read their values gives runtime error. But if undeclared variables are assigned then implicit declaration is done .

Undefined variables are those that are not assigned any value but are declared in the program. Trying to read such variables gives special value called undefined value.

In JavaScript === is strict equality operator ,it returns true only when the two operands are having the same value without any type conversion.

<script>

function favAnimal(button) {

alert('You like '+button.value+'s.');

}

</script>

<input type="radio" name="marsupial" value="kangaroo"

onchange="favAnimal(this)">Kangaroo

<br /><input type="radio" name="marsupial" value="Opossum"

onchange="favAnimal(this)">Opossum

<br /><input type="radio" name="marsupial" value="Tasmanian Tiger"

onchange="favAnimal(this)">Tasmanian Tiger

To disable an HTML object in JavaScript use below line of code...

document.getElementById("myObject").disabled = true;

Changing the contents of an element is a much better solution. When the method showStatus is invoked it will change the content of the span.

function showStatus(message) {

var element = document.getElementById("mystatus");

element.textContent = message; //for Firefox

element.innerHTML = message; //for IE (why can't we all just get along?)

return true;

}

<span id="mystatus">Test. </span>

<script type="text/javascript">

function pseudoHitMe() {

alert("Ouch!");

}

</script>

<a href="javascript:pseudoHitMe()">hit me</a>

<a href="javascript.shtml"

onmouseover="window.status='Hi There!';return true"

onmouseout="window.status='';return true">Look at the Status bar</a>

Look at the Status bar as your cursor goes over the link.

Below line will help us how to create a popup warning box in JavaScript....

alert('Warning: Please enter an integer between 0 and 100.');

Below line will help us how to create a Confirmation box in JavaScript....

confirm("Do you really want to launch the missile today. HuM?");