jQuery Syntax

The jQuery is start with document ready event which is contain by Script tag. All jQuery code is written in script tag.

The $(document).ready(handler) statement is called ready event. The handler is a function 
that execute only when if document is ready to be manipulated.

<script type="text/javascript">
$(document).ready(function(){
  // jQuery methods go here...
});
</script>

You can also write following code if you don't want document ready event.
<script type="text/javascript">
$(function(){
  // jQuery methods go here...
}); 
</script>

The jQuery code start with the dollar sign ($) and ends with a semicolon (;).  
The syntax of jQuery code is following: 
$(selector).action();

The exaplanation of jQuery syntax is following.
A $ sign to define jQuery.
A (selector) to "query (or find)" HTML elements.
A jQuery action() to be performed on the element(s).

There are following examples of jQuery code.

$(this).hide() - hides the current element.
$("a").hide() - hides all <a> elements.
$(".first").hide() - hides all elements with class="first".
$("#first").hide() - hides the element with id="first".