1) With HTML plus JS you are in full control, in the look and response of your web page. The use of CSS (cascaded style sheets) will make the look of the web pages in your web site consistent, The use of PHP in your site would enhance it and gives it more functionality. The presentaation of this page as well as building web sites using joomla and drupal used CSS file in order to achieve a consistent look.
2) The basic idea of HTML is the use of tags to tell the browser how and what to display in your page. Basically, there are 2 types of tags one having a start and an end tag and the other has only one tag to describe the action or the function. Examples are <b> </b> bold and <img src="/joomla/imagename3.ext">
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