Most of the HTML elements are surrounded by start and end tags to specify the starting and end of the element. There is a special group of elements that only have start tags and does not contain any content within it, these elements are called void elements. Void elements doesn’t have ending tags and can only have attributes but do not contain any kind of content. These elements can have backslash before ending of start tag but that is completely optional. Example of such elements are <br>, <hr>, <img>, <input>, <link>, <base>, <meta>, <param>, <area>, <embed>, <col>, <hr>, <source> etc.