The CSS Visual Formatting is a model corresponding to an algorithm which processes and transforms each element of the document to generate one or more boxes that conform to CSS Box Model.
The layout of generated boxes depends on several properties such as −
CSS Box Generation of processed elements −
Let’s see an example of block level box generation −
<!DOCTYPE html> <html> <head> <title>HTML Heading</title> <style> form { width:70%; margin: 0 auto; text-align: center; } * { padding: 2px; margin:5px; } input[type="button"] { border-radius: 10px; } #headingPreview h2{ background-color: #DC3545; } </style> </head> <body> <form> <fieldset> <legend>HTML Heading</legend> <input type="text" id="textSelect" placeholder="Type Heading Here..."> <div id="radioBut"> <label>H1</label><input class="radio" type="radio" name="heading" value="h1" checked > <label>H2</label><input class="radio" type="radio" name="heading" value="h2"> <label>H3</label><input class="radio" type="radio" name="heading" value="h3"> <label>H4</label><input class="radio" type="radio" name="heading" value="h4"> <label>H5</label><input class="radio" type="radio" name="heading" value="h5"> <label>H6</label><input class="radio" type="radio" name="heading" value="h6"> </div> <div>Heading Preview: <span id="headingPreview">Output will show up here</span></div> <input type="button" onclick="changeHeading()" value="Preview"> </fieldset></form> <script> var textSelect = document.getElementById("textSelect"); var headingPreview = document.getElementById("headingPreview"); function changeHeading() { if(textSelect.value === '') headingPreview.innerHTML = 'Write a Heading'; else{ for(var i=0; i<6; i++){ var radInp = document.getElementsByClassName('radio')[i]; if(radInp.checked === true && textSelect.value !== ''){ headingPreview.innerHTML = '<'+radInp.value+'>'+textSelect.value+'</'+radInp.value+'>'; headingPreview.innerHTML += '<'+radInp.value+'>'+textSelect.value+'</'+radInp.value+'>'; } } } } </script></body></html>
This will produce the following output −
After clicking ‘Preview’ button with text field empty −
After clicking ‘Preview’ button with text field not empty and ‘h2’ radio button checked −
Let’s see an example for inline level box generation −
<!DOCTYPE html> <html> <head> <title>em element</title> <style> form { width:70%; margin: 0 auto; text-align: center; } * { padding: 2px; margin:5px; } input[type="button"] { border-radius: 10px; } em{ background-color: #FF8A00; } </style> </head> <body> <form> <fieldset> <legend>em-element</legend> <label for="textSelect">Formatter: </label> <input id="textSelect" type="text" placeholder="John Doe"> <input type="button" onclick="convertItalic()" value="Check"> <div id="divDisplay"></div> </fieldset> </form> <script> var divDisplay = document.getElementById("divDisplay"); var textSelect = document.getElementById("textSelect"); function convertItalic() { for(i=0; i<2; i++){ var italicObject = document.createElement("EM"); var italicText = document.createTextNode(textSelect.value); italicObject.appendChild(italicText); divDisplay.appendChild(italicObject); } } </script> </body> </html>
This will produce the following output −
Before clicking ‘Check’ button −
After clicking ‘Check’ button −