Question 1

How can I add and remove an Html element dynamically using javascript?

Accepted Answer

Below is the javascript code which is used to add and remove div elements dynamically.Here the div tags are added in one base div tag container.

Question 2

How to resolve error message ‘String constants must end with a double quote.’

Accepted Answer

To resolve this check out PRB: The Tag Is Treated As a Closing Tag When Inside a Quoted String

Question 3

Is there a JavaScript Quick Reference Guide?

Accepted Answer

Here is a JavaScript Quick Reference Guide in Poster Format that you can print out and refer easily. Covers the older and newer version of DOM and IE and Mozilla.
Danny Goodman’s JavaScript and Browser Objects Quick Reference

Question 4

How can users use ASP.NET’s server side methods to implement client scripts?

Accepted Answer

Here is an article from ftp online: Implement Client Scripts

Question 5

What approaches can users use to add Client-side script code?

Accepted Answer

Here is an article from ftp online: Add Client-Side Script Code

Question 6

Is it possible to identify the source webpage where I came from?

Accepted Answer

You can identify the source webpage using the document.referrer command. The document object is the page currently loaded in the browser window – presumably your Web page. The referrer property is the page the visitor was at immediately prior to visiting the current page. You can code it as,

Question 7

How can you do ClientSide Validation?

Accepted Answer

Client-side validation is enabled by default. If the client is capable, uplevel validation will be performed automatically. To disable client-side validation, set the page’s ClientTarget property to ‘Downlevel’ (‘Uplevel’ forces client-side validation). Alternatively, you can set an individual validator control’s EnableClientScript property to ‘false’ to disable client-side validation for that specific control.

Question 8

Can I access the query string using JavaScript?

Accepted Answer

A query string is an optional part of a URL that goes after the file name and begins with a questionmark. For eg the query string will be as http://www.sitedemo/com/home.htm?newquerystringadded. Here querystringvalue is the newquerystringadded. The query string can be added and it can be retrieved as shown,

Question 9

How can you make the text to scroll in the window’s status bar?

Accepted Answer

The text can be made to scroll using the javascript codings as below.

Question 10

How can I know if the client browser supports active scripting

Accepted Answer

You can detect and intercept the capabilities of your client using the namespace System.Web.HttpBrowserCapabilities : VB.NET C# For more details Refer: Detecting Browser Types in Web Forms

Question 11

How can I resize the window?

Accepted Answer

You can resize a window with JavaScript using ‘window.resizeTo(valueX,valueY)’.

<script> 
function ResizeWindow()
{
	window.resizeTo(800,800);
}	
</script>

Note also that the parameters of resizeTo() have different meaning in different browsers. In Internet Explorer the parameters specify the outer size of the window, while in Netscape Navigator they refer to the inner size (which does not include the window borders, toolbar, status bar, title bar, and the address line). The ‘window.resizeBy()’ method is slightly different than it’s ‘resizeTo()’ which changes the windows dimensions by number of pixels from it’s current size.

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Question 12

How can you resize the html elements dynamically?

Accepted Answer

Html elements can be resized dynamically by using the style properties. In the below example the TextArea size is increased dynamically on clicking the button.

Question 13

How can you avoid postback on submit button?

Accepted Answer

The postback on submit button can be avoided by giving return=false in the event handler function as below.

Question 14

How can you identify the drives available in the System?

Accepted Answer

The drives available in system can be identified using the following code.

Question 15

How can I check whether left or right mouse button has been clicked?

Accepted Answer

To determine whether the user clicked the left or right button, you can use the following properties. Event.which in Netscape Navigator event.button in Internet Explorer If the value of these properties is 1, the event occurred for the left button. In the following example, the onMouseDown event handler displays the messages Left button or Right button, depending on the mouse button you actually have clicked. The messages will appear on your browser’s status bar. Click or right-click anywhere on this page to see it work:

Question 16

How can we check whether a function exists in javascript?

Accepted Answer

We can check the existence of a function by Window.FunctionName as shown below, where the FunctionName is the name of the function,whose existence has to be checked.

Question 17

How can i resize the dialog window?

Accepted Answer

You can size a window with JavaScript using ‘window.resizeTo(valueX,valueY)’.

<script>
functionResizeWindow()
{
	window.resizeTo(800,800);
}	
</script>

Note also that the parameters of resizeTo() have different meaning in different browsers: in Internet Explorer the parameters specify the outer size of the window, while in Netscape Navigator they refer to the inner size (which does not include the window borders, toolbar, status bar, title bar, and the address line). The ‘window.resizeBy()’ method is slightly different than it’s ‘resizeTo()’ which changes window’s dimensions to a certain number of pixels from it’s current size.

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Question 18

How can you get the X Co-ordinates Y Co-ordinates values during the Mouse Movement?

Accepted Answer

The X and y co-ordinates during the mouse movement can be obtained by the following codings.

Question 19

How can you make a piece of text get moving along the mouse Movement?

Accepted Answer

We can make text to move along the mouse using javascript as given below,

Question 20

How can the a client side function be called on a button click event?

Accepted Answer

In 2.0 Button control has a property OnClientClick which is used to call a client side function before postback.

Question 21

How can you generate a clock in javascript?

Accepted Answer

A clock can be generated using the javascript function as given below.

Question 22

How can I use a Timer Control to refresh a page automatically at a specified interval

Accepted Answer

Question 23

How to pop up a message box when no item in the dropdownlist is selected before postback?

Accepted Answer

Make sure to add a ListItem with Text=’Please Choose’ and Value =”. Add a RequiredFieldValidator with ControlToValidate= <Dropdownlist1> and Display=’Dynamic’ Add a ValidationSummary with ShowMessageBox =true

Question 24

How can I make a Textbox a mandatory field if a checkbox is checked on a button click event in the client side?

Accepted Answer

VB.NET C#

Question 25

How to disable a Dropdownlist once someone has selected an item in the Dropdownlist

Accepted Answer

VB.NET C#

Question 26

How to change the BackgroundColor of a page based on the value selected in a DropdownList

Accepted Answer

VB.NET C#

Question 27

How to display a message in the status bar of a browser window

Accepted Answer

Question 28

How to rotate a Label Text

Accepted Answer

Question 29

How to check/ uncheck a checkbox based on the text entered in textbox

Accepted Answer

In Page_Load VB.NET C#

Question 30

How to disable the right click option on a web page

Accepted Answer

Note :User can still do a View/Source in their browser menu.

Question 31

How to resize two

tags on a webform

Accepted Answer

Note : if the DIV has no borders, clientHeight works. If you are going to be using a border or margins, then use offsetHeight

Question 32

How to hide a control using javascript

Accepted Answer

Question 33

How to emit client-side javascript blocks from VB.NET/C#

Accepted Answer

The RegisterStartupScript method emits the script just before the closing tag of the Page object’s

Question 34

How can the ‘Enter’ key be disabled?

Accepted Answer

In order to avoid the Form Submission by pressing the ’Enter Key’ you have to write following code on the KeyPress Event Of the Body Tag

Question 35

Is there Trim function available in Javascript?

Accepted Answer

There is no predefined trim function available. The function written below is used to Trim white spaces.

Question 36

How can we check whether the cookie is enabled?

Accepted Answer

It can be done by checking the read only property navigator.cookieEnabled. navigator.cookieEnabled will give the value true/false based on the browser support for cookies.

Question 37

How the browser name can be detected?

Accepted Answer

We can use navigator.appName property, to identify the browser we are using .For Netscape browsers, the value of navigator.appName is ‘Netscape’. For Microsoft Internet Explorer browsers,the value of navigator.appName is ‘Microsoft Internet Explorer’ . The following code is used for browser detection.

Question 38

How can i form a regular expression which identifies a valid whole number without decimal places?

Accepted Answer

The regular expression used to identify only the numbers is var regexp = /\D|\./.

Question 39

How to parse the files/folders in the client’s file system?

Accepted Answer

Here is a technique usable in IE Only

Question 40

How to create files on the client m/c using JavaScript?

Accepted Answer

Here is a technique usable in IE Only.

Question 41

How to show Modal and Modeless dialog windows in Javascript?

Accepted Answer

When you show a modal dialog the window remains on top of other windows until the user explicitly closes it. When you show a modeless dialog the window remains on top of other windows, but you can still access the other windows.

Question 42

Are there any resources regarding the Mozilla specific Browser Objects and CSS information

Accepted Answer

Official Gecko DOM Reference: Gecko Dom Reference Here is a very useful list of custom CSS styles specific to Mozilla: XUL Planet

Question 43

Why does the SmartNavigation does not work on the live server but works perfectly on the Development Machine

Accepted Answer

May be the domain does not have access to the aspnet_client folder which is located in the wwwroot folder. i.e the website is not able to find the scripts for smart navigation. So set up a virtual folder to the wwwroot/aspnet_client and it will fix the problem.

Question 44

How to create dynamic javascripts in server side code based on server side variables?

Accepted Answer

Here’s and example: VB.NET C#

Question 45

How to get the confirmation of Yes/No from a javascript pop-up and display the value on the page

Accepted Answer

Code Behind Client Side To display the Yes/No value selected by user, in your code behind file:

Question 46

Why can’t I open a new browser window from within server code?

Accepted Answer

Server code executes on Server, whereas the new window is created on the client. You need to use client-side script to open new window.

Question 47

How to set the background color of a web page using code behind?

Accepted Answer

Yes In the body tag, add runat=’server’ and give the tag an id (e.g. id=’bodyID’). In the class definition in the code-behind, add VB.NET C# In code, use the attributes collection to set the bgcolor attribute: VB.NET C#

Question 48

How to determine if the Browser supports javascript?

Accepted Answer

VB.NET C#

Question 49

How can I change the scroll bar color

Accepted Answer

Use Style Sheet to change the color of scroll-bar

Question 50

How to change a Label element’s text in javascript

Accepted Answer

Question 51

Can I modify WebUIValidation.js

Accepted Answer

Extract from MSDN : For more details refer ASP.NET Validation in Depth

Question 52

Does JavaScript support hashtables/ hash tables or dictionary type data structures?

Accepted Answer

All Objects in JavaScript implicitly support hash table like syntax by virtue of behaving as Associative Arrays. Properties of an object can be accessed in 2 ways as shown below:

object.property = value;
object['property'] = value;

So, when used in a hash table like syntax as shown above, you will be simply creating dynamic properties and assigning values to those properties.

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Question 53

How to open a new window without IE menus and toolbars on click of a button

Accepted Answer

VB.NET C#

Question 54

How to open a browser window with maximum size on click of a button

Accepted Answer

VB.NET C#

Question 55

How to open a new Window using javascript function from a Link button

Accepted Answer

VB.NET C# You can also check out Andy Smith’s RemoteWindow Control

ASP.NET FAQ - Client Side Scripting

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ASP.NET FAQ - Client Side Scripting

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