Class (.tagclass)

Select all elements that have a class of 'tagclass'.
Examples

1- $('.tagclass') selects all elements that have a class of tagclass
2- $('p.tagclass') selects all paragraphs that have a class of tagclass
3- $('.tagclass.otherclass') selects all elements that have a class of both tagclass and otherclass

For class selectors, jQuery uses JavaScript's native getElementsByClassName() function if the browser supports it. Otherwise, it checks the .className attribute of each element.