Updated April 4, 2023
Introduction to XML Interview Questions
XML or Extensible Markup Language is a text-based mark-up language that allows us to store data in structure format, XML is not a programming language it is used to format data or content usually for storage, transmission, processing by a program, it is mostly used by developers for designing, developing, and maintaining interface, the tags are not predefined in XML so that we can define our own tags to simplicity.
Interview Questions
An interview is a formal one-on-one conversation between the interviewer and the interviewee in which the interviewer is going to ask questions to the interviewee to find someone suitable for the job which they are offering and the interviewer responds by giving information.
XML interview questions with answers:
1) Explain how XML is Extensible Markup Language?
At first, as we know that XML is not a programming language, it is used to format data or content which is usually for storage, transmission, or processing by a program, it does not say anything about data like programming languages can.
It is a markup language because it has a set of rules, tags, that defines the structure and format of text while presenting text and some markup languages especially those that used in word processors that only describe the appearances such as bold, italic, only be used for display not easily reusable.
XML is extensible means it is a meta-language so we can extend its specification to define new markup language and is also playing an important role in the exchange of a variety of data on the web.
2) What is HttpRequest in XML?
The HttpRequest in XML can be used to requesting data from a web server, it means let us assume we as a developer can retrieve data and can update the web page without reloading, after the page loaded we can request data from a server and similarly can receive the data from the server and the data sent in the background. It is the read-only property in XML which returns XML or Html documents and is retrieved by the request.
For example, if we have a web page and there is an input field when we type character in the input field the XMLHttpRequest is sent from the web page to the server and it suggests some names.
3) What is getResponseHeader() method?
The XMLHttpRequest has getResponseHeader() method which is used to return a string containing the text of a particular header value, it returns the specific header information from the response server, usually the response is parsed as text and if we want entire header information then we can use getAllResponseHeader() method. A response header contains information about length, server-type, content-type, modified-date, etc.
4) Is HTML can be replaced with XML?
None of either language can replace each other but yes XML is a good alternative for HTML because it has great features like new elements that can be defined there and it can create mark up for storing data and processing it.
5) Tell any five differences between XML and HTML?
XML:
- XML describes the content only.
- In XML we can make our own tags.
- This is a content-oriented language.
- XML has multiple outputs.
- It has a standard structure for data validation.
HTML:
- It describes the structure and appearance of data.
- It has fix set of tags that are not able to change.
- It is presentation-oriented.
- It has a single output form.
- It does not have data validation.
6) Why use a DTD?
DTD stands for Document Type Definition and the element of XML documents is defined by it and we can say that the structure of the document with a list of elements and attributes are defined by the DTD. We have to use DTD to validate our own data as it is working for validation in XML. It is an in-built application for sharing data independently. If we are using any application that can use a standard set of DTD to verify data that we receive outside which we want to be valid. That is why DTD is used in XML.
7) What is the <xsl:element> tag in XML?
This tag is used to create an element node in the output document. This tag is used for putting the value of the selected node as per the Xpath expression. The XSLT is the most important part of the XSL, in another way we can say that the XSLT transform an XML source-tree into an XML tree which is a result tree, let us see the syntax of it as follow,
<xsl:value-of
select = Expression
disable-output-escaping = “yes” | “no”>
</xsl:value-of>
Where,
select: is used to specify the Xpath
disable-output-escaping: It is by default “no”, if “yes” then XML character will not escape from the text.
And the XSLT is the Extensible Stylesheet Language Transformation which is used for transforming an XML document into another format that uses Xpath to perform matching of nodes which we were used for transformation and we get another document after applying XSLT to it, and the document may be of an XML document, Html document, and text document.
8) What do you mean by nested elements in XML?
The nested elements mean the root element can be nested with one or two elements and the nesting of the element will make it easier to understand the XML document.
9) Why should we go for XML editor instead of Html?
Because XML editor allows to build error-proof document and also it is validated by schema or DTD and also XML editor can check open tags as well as close tags with validation. It also checks the color code on a syntax of XML.
Conclusion
In the above article, we explained some questions related to the XML which are may be asked in the interview by the interviewer, if you are starting to learn an extensible language like XML then this will help to measure your skills, for a good interview practice more with these questions with details.
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