First paragraph.
Second paragraph.
function Demo(){
// Get a jQuery stack containing the body tag.
var jBody = $( document.body );
// Alert side of stack (number of elements).
alert( jBody.size() );
// Get a jQuery stack containing all P tags.
var jP = $( document.getElementsByTagName( "p" ) );
// Alert side of stack (number of elements).
alert( jP.size() );
}