Difference Between " . " and " # " Selector in CSS Last Updated : 12 Jul, 2025 Comments Improve Suggest changes Like Article Like Report In CSS, selectors define which HTML elements receive specific styles.Class Selector (.): Targets elements with a specified class attribute, allowing multiple elements to share the same styling.ID Selector (#): Targets a single element with a unique ID attribute, ensuring that styles are applied to one specific element on the page.Id selector("#")In CSS, the ID selector (#) targets a single, unique element based on its id attribute. Since IDs should be unique within an HTML document, this selector styles a specific element. HTML <html> <head> <style> #container { width: 400px; height: 150px; border: 2px solid black; text-align: center; } </style> </head> <body> <div id="container"> <b class="selector"> CSS Selector id(#) </b> </div> </body> </html> The #container selector applies styles to the HTML element with id="container".The width, height, border, and text-align properties define the appearance of this specific element.Class Selector(".")In CSS, the class selector (.) targets HTML elements based on their class attribute, allowing multiple elements to share the same styling. HTML <html> <head> <style> .container { width: 400px; height: 150px; border: 2px solid black; text-align: center; } </style> </head> <body> <div class="container"> <b class="selector">CSS Selector class(.)</b> </div> </body> </html> The .container selector applies styles to all HTML elements with the class="container" attribute.The specified width, height, border, and text-align properties define the appearance of these elements.Difference between class (".") and id ("#") SelectorsAspectClass Selector (".")Id Selector ("#")UsageTargets elements with a specific class attributeTargets an element with a unique id attributeUniquenessCan be applied to multiple elementsMust be unique within a page, used for one elementMultiplicityAn element can have multiple classesAn element can have only one idApplicationUsed for general styling across multiple elementsUsed for specific, single-element stylingSyntax.class_name { /* properties */ }#id_name { /* properties */ } Comment More infoAdvertise with us Next Article CSS Introduction G g_ragini Follow Improve Article Tags : Technical Scripter Web Technologies CSS Technical Scripter 2019 CSS-Misc +1 More Similar Reads CSS Tutorial CSS stands for Cascading Style Sheets. It is a stylesheet language used to style and enhance website presentation. CSS is one of the three main components of a webpage, along with HTML and JavaScript.HTML adds Structure to a web page.JavaScript adds logic to it and CSS makes it visually appealing or 7 min read CSS Introduction CSS (Cascading Style Sheets) is a language designed to simplify the process of making web pages presentable.It allows you to apply styles to HTML documents by prescribing colors, fonts, spacing, and positioning.The main advantages are the separation of content (in HTML) and styling (in CSS) and the 4 min read CSS Syntax CSS is written as a rule set, which consists of a selector and a declaration block. The basic syntax of CSS is as follows:The selector is a targeted HTML element or elements to which we have to apply styling.The Declaration Block or " { } " is a block in which we write our CSS.HTML<html> <h 2 min read CSS Selectors CSS Selectors are used to target HTML elements on your pages, allowing you to apply styles based on their ID, class, type attributes, and more. There are mainly 5 types of selectors.Basic CSS Selectors: These are used to target elements by tag, .class, or # ID for fundamental styling needs.Combinato 7 min read CSS Comments CSS comments are used to add notes or explanations to your code, helping you and others understand it better. They start with /* and end with */ and can be used for both single-line and multi-line comments. Note: Comments are ignored by browsers, so they won’t affect how your webpage looks or works. 2 min read CSS Colors CSS colors are used to set the color of different parts of a webpage, like text, background, and borders. This helps make the page look more attractive and easier to read. You can define colors using names, hex codes, RGB values, and more.You can try different formats of colors here- #content-iframe 5 min read CSS Borders Borders in CSS are used to create a visible outline around an element. They can be customized in terms ofWidth: The thickness of the border.Style: The appearance of the border (solid, dashed, dotted, etc.).Color: The color of the border.You can try different types of borders here- #custom-iframe{ he 5 min read CSS Margins CSS margins are used to create space around an element, separating it from neighboring elements and the edges of the webpage. They control the layout by adjusting the distance between elements, providing better organization and readability.Syntax:body { margin: value;}HTML<html> <head> 4 min read CSS Height and Width Height and Width in CSS are used to set the height and width of boxes. Their values can be set using length, percentage, or auto.Width and HeightThe width and height properties in CSS are used to define the dimensions of an element. The values can be set in various units, such as pixels (px), centim 4 min read CSS Outline CSS outline is a property used to draw a line around an element's border. It does not affect the layout, unlike borders. It's often used to highlight elements, providing a visual emphasis without altering the dimensions of the element.Syntaxselector{ outline: outline-width outline-type outline-color 4 min read Like