I had a requirenment to display a little tooltip like pop-up on mouseover(hoverover) of the Links(Single LineText) displayed using a DataView WebPart.The tooltip would contain description of the Link again puled in from the List.

Something like:

"Send Us Feedback" is a Title(named as Links) in the List and "Tell us what you think.." is Links description.

To do this we need to add a CSS for creating a tooltip in DataView's XSLT.
The List that I used had following columns:

1. Links

2. Descriptions
3. URL for the Link.

In Data view XSLT header put the following CSS for creating a tooltip pop-up

Refer the CSS class "link" to make a pop-up with description(defined in span)

So you get the POP-UP Now.

Another requirenment was to open up the Link("Send us the feedback" in this case) in a New window. The Url for new window is also pulled in from same List.

This is done by using the below code:

You can also add the Javascript function in header, and call in attribute like :

About XSLT

XSLT is a language for transforming XML documents into XHTML documents or to other XML documents.

XPath is a language for navigating in XML documents.

What is XSLT?
XSLT stands for XSL Transformations
XSLT is the most important part of XSL
XSLT transforms an XML document into another XML document
XSLT uses XPath to navigate in XML documents
XSLT is a W3C Recommendation
XSLT = XSL Transformations
XSLT is the most important part of XSL.

XSLT is used to transform an XML document into another XML document, or another type of document that is recognized by a browser, like HTML and XHTML. Normally XSLT does this by transforming each XML element into an (X)HTML element.
With XSLT you can add/remove elements and attributes to or from the output file. You can also rearrange and sort elements, perform tests and make decisions about which elements to hide and display, and a lot more.

A common way to describe the transformation process is to say that XSLT transforms an XML source-tree into an XML result-tree.

XSLT uses XPath to find information in an XML document. XPath is used to navigate through elements and attributes in XML documents.

How Does it Work?
In the transformation process, XSLT uses XPath to define parts of the source document that should match one or more predefined templates. When a match is found, XSLT will transform the matching part of the source document into the result document.