Select By Element ID $("#id")

This jQuery selector selects one element by its id. For example to select element <div id='someID'> use $('#someID')

$("#id")

$("#id") selects only one element with matching id

#id is the id given to HTML element e.g. <div id='someID'>
Example 1: $("#someID") will select element with id='someID'
<div id='someID'>div-1</div>
<div class='someClass'>div-2</div>
<p>p-1</p>
<div>div-3</div>
<span>span-1</span>

Demo: Find an element with id='d1'

HTML
 
<div id="d1">DIV 1</div>
<div>DIV  2</div>
<div>DIV  3</div>
jQuery code
$("#d1");
Demo

DIV 1
DIV 2
DIV 3
jQuery selector $("#id")