The first option will apply the jQuery library methods to a DOM object (in this case, the document object).
The second option will select every <div> that has the <id> attribute set to “mydiv”.
The third option will select all of the <p> tags with the class of “first”.
This option will select from the page all <p> tags that have a title of “Hello”. Techniques like this enable the use of much more semantically correct (X)HTML markup, while still facilitating the DOM scripting required to create complex interactions.
This enables the selection of all of the <p> tags on the page that have a title that starts with the letter H.