Latest Technical Interview Answers - 15

Latest Technical Interview Answers - 15

How can Javascript be used to personalize or tailor a Web site to fit individual users?
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Javascript allows a Web page to perform "if-then" kinds of decisions based on browser version, operating system, user input, and, in more recent browsers, details about the screen size in which the browser is running. While a server CGI program can make some of those same kinds of decisions, not everyone has access to or [...]

How to set a HTML document’s background color?
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document.bgcolor property can be set to any appropriate color.

What can Javascript programs do?
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Generation of HTML pages on-the-fly without accessing the Web server. The user can be given control over the browser like User input validation Simple computations can be performed on the client’s machine The user’s browser, OS, screen size, etc. can be detected Date and Time Handling

Where are cookies actually stored on the hard disk?
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This depends on the user’s browser and OS. In the case of Netscape with Windows OS, all the cookies are stored in a single file called cookies.txt c:\Program Files\Netscape\Users\username\cookies.txt In the case of IE,each cookie is stored in a separate file namely username@website.txt. c:\Windows\Cookies\username@Website.txt

How to add Buttons in Javascript?
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The most basic and ancient use of buttons are the ” submit” and ” clear” , which appear slightly before the Pleistocene period. Notice when the ” GO!” button is pressed it submits itself to itself and appends the name in the URL. < form action=" " name=" buttonsGalore" method=" get" > Your Name: < input type=" [...]

What are a fixed-width table and its advantages in Javascript?
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Fixed width tables are rendered by the browser based on the widths of the columns in the first row, in Javascript resulting in a faster display in case of large tables. Use the CSS style table-layout:fixed to specify a fixed width table. If the table is not specified to be of fixed width in Javascript, the [...]

How do you target a specific frame from a hyperlink in Javascript?
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Include the name of the frame in the target attribute of the hyperlink in Javascript. < a href=”http://www.globalguideline.com” target=”myframe”> Global Guide Line< /a>

How to create arrays in Javascript?
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We can declare an array like this var scripts = new Array() We can add elements to this array like this scripts[0] = ” PHP” scripts[1] = ” ASP” scripts[2] = ” Javascript” scripts[3] = ” HTML” Now our array scripts have 4 elements inside it and we can print or access them by using their index number. Note that index number [...]

How do you convert numbers between different bases in Javascript?
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Use the parseInt() function, that takes a string as the first parameter, and the base as a second parameter. So to convert hexadecimal 3F to decimal, use parseInt (” 3F” , 16)

What are Javascript Data Types?
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Javascript Data Types are Number, String, Boolean, Function, Object, Null, Undefined

How to detect the operating system on the client machine?
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In order to detect the operating system on the client machine, the navigator.appVersion string (property) should be used.

How do you submit a form using Javascript?
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Use document.forms[0].submit() (0 refers to the index of the form – if we have more than one form in a page, then the first one has the index 0, second has index 1 and so on).

What is Javascript?
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Javascript is a general-purpose programming language designed to let programmers of all skill levels control the behavior of software objects. The language is used most widely today in Web browsers whose software objects tend to represent a variety of HTML elements in a document and the document itself. But the language can be–and is–used with [...]

Explain about the Boolean functions present in Javascript?
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Three Boolean operators are present in Javascript they are 1) && 2) II 3) / All the operators are regarded as true unless the Javascript regards them as false. You can define these operators to make as statement false number0, null, undefined, or a string of length 0, etc. Boolean function performs these conversions explicitly.

Explain about strings in Javascript?
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Strings are represented as a sequence of characters in Javascript. Strings can be created when you place characters between double quotations or single quotations. Individual characters can be accessed by arrays.

Explain about defining numbers in Java script?
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Java script represents numbers in the form of IEEE-754 doubles. This form of representation provides accuracy upto 14-15 significant digits. They represent fractions but not the decimal numbers to an extent. To perform explicit numeric conversion you can use Number constructor.

Explain about arrays in Java script?
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Array maps everything from an integer to Values. Objects map everything from values to integers, Javascript specialize in certain special functions through which they can include integer indicies in their behavior. Large indicies can be removed if the length of the array specified is very small.

Explain about Cross site scripting?
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Cross site scripting raises security threats during execution and secured data transfer through web sites. It uses same origin policy. When a malicious script is made to run it discloses private information to the wrong person. This occurs because some one clicks on the request sent by the wrong doer.

What are the rare cases when Java script will not function?
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These are the following cases when Java script will not function. 1) An old browser which doesn’t support DOM. 2) PDA or Mobile Phone will not execute Java script. 3) Security reasons will not allow optimal performance of Jscript. 4) Speech browsers will not allow the functioning of Jscript.

What are the precautions taken by the web browsers to contain malicious activity with Java script?
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Java script activities are restricted by web browsers in two ways they are. 1) First scripts run in sandbox which performs the most basic functions such as executing or running the code or script. This doesn’t allow programming activities. 2) scripts present in one site cannot have access to other sites; this is done with the help [...]