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CSS horizontal and vertical centering - 2

Windows : Internet Explorer 5.01+, Firefox 1.0+, Google Chrome, Opera 7.03+, Safari 3.1+, SeaMonkey 1.0+ [ 1 ].

Linux : Firefox 1.0+, Chromium, Opera 7.03+, SeaMonkey 1.0+ [ 2 ].

Centering the content of a web page in the viewable area of a browser by means of CSS. A box to contain the whole content of the page is CSS centered horizontally and vertically: [ Open demo page ]

HTML / XHTML. Code:

<!DOCTYPE html>

<html>

<head>

<title>CSS horizontal and vertical centering - 2</title>

<link rel="stylesheet" type="text/css" href="css.css" />

</head>

<body>

<div class="spacer">&nbsp;</div>

<div class="wrapper">

<div class="pagecontent">&nbsp;</div>

</div>

</body>

</html>

CSS. Code:

html {height: 100%; margin: 0px;}

body height: 100%; margin: 0px;}

.spacer {position: relative; top: 0px; left: 0px; height: 50%; width: 100px; float: left; margin: 0px 0px -250px 0px; background: #999;}

.wrapper {position: relative; top: 0px; left: 0px; height: 500px; width: 100%; clear: both; background: #a3ddc4;}

.pagecontent {position: relative; top: 0px; left: 0px; height: 500px; width: 800px; margin: 0 auto; background: #ff6f6f;}

The .pagecontent box is for the page content. It must be of a fixed height and width in units like px's or em's - not in percents. Height and width may be larger than web browser viewable area, but here the more practical case is discussed - when the height and width of .pagecontent are smaller than those of the web browser viewable area.

The .pagecontent box is horizontally centered by its "margin: 0 auto".

.Wrapper creates a space where .pagecontent is centered horizontally. .Wrapper's width is 100% for centering at various web browser viewable area sizes. The height has to be equal to the one of .pagecontent.

.Spacer centers .wrapper with .pagecontent in it vertically inside browser viewable area. Its width may be any. The height is 50% - that places the top edge of .pagecontent vertically in the middle of the browser viewable area. The bottom margin of .spacer equal to half the .pagecontent height centers .pagecontent and its contents vertically in the web browser viewable area of a current height.

This method is reliable in all major modern web browsers. It also works in older browsers like Internet Explorer 6 or earlier versions of Maxthon. But the height of box for page content has to be assigned explicitly and if it is changed - the size of .spacer bottom margin must be changed accordingly as well. There is another way of CSS horizontal and vertical centering, with CSS code easier to maintain, even if not suitable for older web browsers: CSS horizontal and vertical centering - 1.


[ 1 ]

As well as Netscape 7.2+, Mozilla 1.5+.

[ 2 ]

As well as Netscape 7.2+, Mozilla 1.5+.


Aliosque subditos et thema

 

JavaScript form submit

 

Submitting a form using JavaScript. A dropdown list (form + select + multiple options) is processed without any submit button. Example: --- Select a page --- Linux Windows DOS HTML / XHTML. Code: <form action="action.php" method="post"> <select name="page" required="required" onchange="this.form.submit()"> <option value="" selected="selected" disabled="disabled"> --- Select a page --- </option> <option value="http://www.kompx.com/en/os/linux-1.htm">Linux</option> <option value="http://www.kompx.com/en/os/windows-1.htm">Windows</option> <option value="http://www.kompx.com/en/os/dos-1.htm">DOS</option> </select> <noscript><input type="submit" value="Submit" /></noscript> </form> When an option has been chosen from the dropdown list, the form's state is changed. So the onchange event occurs and JavaScript code in onchange is executed: the process of the form submission in started by the script, not by clicking submit button which is absent. Some server-side script [ 3 ] is meant then to handle the form action. The script is supposed to get what the form sends and have it processed. A PHP script in action.php is used in the example: <?php if (isset($_POST["page"])) {     header("Location: $_POST[page]");     exit; } else {     echo "No options selected"; } $_POST is an array of variables passed to the current script via the HTTP POST method. So $_POST[page] contains the content of the value attribute in a select option. That is, a URL. It is passed from form to PHP script and the script redirects browser to the URL / page selected. HTML code of <noscript><input type="submit" value="Submit" /></noscript> is present in the form as a fallback in case JavaScript happens to be turned off. Then there is a submit button to appear and the form is usable anyway. [ 1 ] As well as Netscape 3.04+, Mozilla 0.6+. [ 2 ] As well as Netscape 3.04+, Mozilla 0.6+. [ 3 ] If a CMS is used, form action may be handled by some of its inbuilt means.

CSS for a range of elements

 

Styling a range of elements. Here from the 1st to the 3rd one - changing background color. Example:         HTML / XHTML. Code: <div>&nbsp;</div> <div>&nbsp;</div> <div>&nbsp;</div> <div>&nbsp;</div> CSS. Code: div:nth-of-type(-n+3) {background: #f66;} /* Extra CSS, just styling the look: */ div {width: 100%; margin-top: 5px; background: #066;} Note: nth-child may also be used instead.