Use the controls to select an element in the target html. The selection
will be shown with a dotted red border.
Then choose an "action" (a jQuery method) to apply to that selection. For example,
choose a lightblue background, and apply it with the jQuery css() call. Or set
it to visible/hidden with show() or hide() jQuery calls.
eval()'d within this page. That statement is echoed in the block "Last Command".
HTML Source is just the source of the "demo" div.