Home Interview Questions and Answers JavaScript Interview Questions and Answers Part-5

javascript41.Can you access Cookie using javascript?
JavaScript can also manipulate cookies using the cookie property of the Document object. JavaScript can read, create, modify, and delete the cookie or cookies that apply to the current web page.

42.How to create a Cookie using JavaScript?
The simplest way to create a cookie is to assign a string value to the document.cookie object, which looks like this −

Syntax −

document.cookie = “key1 = value1; key2 = value2; expires = date”;
Here expires attribute is option. If you provide this attribute with a valid date or time then cookie will expire at the given date or time and after that cookies’ value will not be accessible.

43,How to read a Cookie using JavaScript?
Reading a cookie is just as simple as writing one, because the value of the document.cookie object is the cookie. So you can use this string whenever you want to access the cookie.

The document.cookie string will keep a list of name = value pairs separated by semicolons, where name is the name of a cookie and value is its string value.

You can use strings’ split() function to break the string into key and values.

44.How to delete a Cookie using JavaScript?
Sometimes you will want to delete a cookie so that subsequent attempts to read the cookie return nothing. To do this, you just need to set the expiration date to a time in the past.

45.How to redirect a url using JavaScript?
his is very simple to do a page redirect using JavaScript at client side. To redirect your site visitors to a new page, you just need to add a line in your head section as follows −

<script type=”text/javascript”>

46.How to print a web page using javascript?
JavaScript helps you to implement this functionality using print function of window object. The JavaScript print function window.print() will print the current web page when executed.

47.What is Date object in JavaScript?
The Date object is a datatype built into the JavaScript language. Date objects are created with the new Date( ).

Once a Date object is created, a number of methods allow you to operate on it. Most methods simply allow you to get and set the year, month, day, hour, minute, second, and millisecond fields of the object, using either local time or UTC (universal, or GMT) time.

48.What is Number object in JavaScript?
he Number object represents numerical date, either integers or floating-point numbers. In general, you do not need to worry about Number objects because the browser automatically converts number literals to instances of the number class.

Syntax −

Creating a number object −

var val = new Number(number);
If the argument cannot be converted into a number, it returns NaN (Not-a-Number).

49.How to handle exceptions in JavaScript?
The latest versions of JavaScript added exception handling capabilities. JavaScript implements the try…catch…finally construct as well as the throw operator to handle exceptions.

You can catch programmer-generated and runtime exceptions, but you cannot catch JavaScript syntax errors.

50.What is purpose of onError event handler in JavaScript?
The onerror event handler was the first feature to facilitate error handling for JavaScript. The error event is fired on the window object whenever an exception occurs on the page.

The onerror event handler provides three pieces of information to identify the exact nature of the error −

Error message − The same message that the browser would display for the given error.

URL − The file in which the error occurred.

Line number − The line number in the given URL that caused the error.

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