+
+
+
+
+In this example, we'll use a snapshot of the W3C HTML 4.01 specification for Style Sheets and add a custom dynamic StyleSheet to apply some color and font size changes.
+ +A Progressive enhancement strategy is used to extract a static form on the page into a draggable Overlay. Additionally, one of the form inputs is replaced with a Slider. Enter any valid CSS color value into the other inputs (e.g. #123456, #135, rgb(0,0,0), or red).
Full code listing
+Markup
+The markup as stated above is a local snapshot of the HTML 4.01 spec, but with the following markup added to the end of the <body> to show a progressive enhancement model.
<div id="form_container"> + <form class="yui3-widget-bd" id="theme_form" action="#" method="get"> + <fieldset> + <h3>Update Theme</h3> + <label for="font_size">Font size:</label> + <input type="text" size="3" id="font_size" value="16px"> + + <label for="heading_color">Heading color:</label> + <input type="text" size="12" id="heading_color" value="#005A9C"> + + <label for="link_hover">Link hover backgound:</label> + <input type="text" size="12" id="link_hover" value="#ffa"> + </fieldset> + <input type="submit"> + </form> +</div>+ + +
JavaScript
+ +<script src="../../build/yui/yui-min.js"></script>
+<script>
+// Create a new YUI instance, requiring stylesheet, overlay, slider, and the
+// dd-plugin to make the overlay draggable
+YUI().use("stylesheet","overlay","slider","dd-plugin", function (Y) {
+
+ var myStyleSheet = new Y.StyleSheet(),
+ overlayContent = Y.one('#form_container'),
+ overlay,
+ slider,
+ slider_container,
+ fontSizeInput,
+
+ // Create the Overlay, using the form container as the contentBox.
+ // The form is assigned a class yui-widget-bd that will be automatically
+ // discovered by Overlay to populate the Overlay's body section.
+ // The overlay is positioned in the top right corner, but made draggable
+ // using Y.Plugin.Drag, provided by the dd-plugin module.
+ overlay = new Y.Overlay({
+ srcNode: overlayContent,
+ alignOn: [],
+ width: '225px',
+ align: { points: [ Y.WidgetPositionAlign.TR, Y.WidgetPositionAlign.TR ] },
+ plugins: [ Y.Plugin.Drag ]
+ }).render();
+
+ // Slider needs a parent element to have the sam skin class for UI skinning
+ overlayContent.addClass('yui3-skin-sam');
+
+ // Progressively enhance the font-size input with a Slider
+ fontSizeInput = Y.one('#font_size');
+ fontSizeInput.set('type','hidden');
+ fontSizeInput.get('parentNode').insertBefore(
+ Y.Node.create('6 <span></span> 36'),
+ fontSizeInput);
+
+ slider_container = fontSizeInput.previous( "span" );
+
+ // Create a Slider to contain font size between 6px and 36px, using the
+ // page's current font size as the initial value.
+ // Set up an event subscriber during construction to update the replaced
+ // input field's value and apply the change to the StyleSheet
+ slider = new Y.Slider({
+ length: '100px',
+ min: 6,
+ max: 36,
+ value: parseInt(Y.one('body').getStyle('fontSize')) || 13,
+ after: {
+ valueChange: function (e) {
+ var size = e.newVal + 'px';
+
+ this.thumb.set('title', size);
+ fontSizeInput.set('value', size);
+
+ myStyleSheet.set('body', { fontSize: size });
+ }
+ }
+ }).render( slider_container );
+
+ // The color inputs are assigned keyup listeners that will update the
+ // StyleSheet if the current input value is a valid CSS color value
+
+ // The heading input affects all h1s, h2, and h3s
+ Y.on('keyup', function (e) {
+ var color = this.get('value');
+
+ if (isValidColor(color)) {
+ myStyleSheet.set('h1, h2, h3', { color: color });
+ }
+ }, '#heading_color');
+
+ // The link hover affects the background color of links when they are
+ // hovered. There is no way other than via stylesheet modification to
+ // change pseudo-class styles.
+ Y.on('keyup', function (e) {
+ var color = this.get('value');
+
+ if (isValidColor(color)) {
+ myStyleSheet.set('a:hover', { backgroundColor: color });
+ }
+ }, '#link_hover');
+
+ // Progressive form enhancement complete, now prevent the form from
+ // submitting normally.
+ Y.one('#theme_form input[type=submit]').remove();
+
+ Y.on('submit', function (e) {
+ e.halt();
+ }, '#theme_form');
+
+ // A rudimentary validator to make sure we're not trying to set
+ // invalid color values in StyleSheet.
+ function isValidColor(v) {
+ return /^#[0-9a-f]{3}(?:[0-9a-f]{3})?$/i.test(v) ||
+ /^rgb\(\s*\d+\s*,\s*\d+\s*,\s*\d+\s*\)$/.test(v) ||
+ /^[a-z]{3,}$/i.test(v);
+ }
+
+});
+</script>
+
+
+<script>
+YUI.Env.Tests = {
+ examples: [],
+ project: '../assets',
+ assets: '../assets/stylesheet',
+ name: 'stylesheet-theme',
+ title: 'Adjusting a Page Theme on the Fly',
+ newWindow: 'true',
+ auto: false
+};
+YUI.Env.Tests.examples.push('stylesheet-theme');
+YUI.Env.Tests.examples.push('photo-browser');
+
+</script>
+<script src="../assets/yui/test-runner.js"></script>
+
+
+CSS
+This is the CSS added to the page to skin the Overlay and its content.
+ +<style>
+/* For supporting browsers, the overlay is rendered semi-transparent with
+ * fancy rounded corners */
+.yui3-overlay {
+ background: rgba(128,128,128,0.3);
+ -moz-border-radius: 10px;
+ -webkit-border-radius: 10px;
+ border-radius: 10px;
+ padding: 7px;
+ cursor: move;
+}
+.yui3-overlay-content {
+ background: rgba(205,205,205,0.3);
+ -moz-border-radius: 10px;
+ -webkit-border-radius: 10px;
+ border-radius: 10px;
+ padding: 1px;
+}
+.yui3-overlay form {
+ background: #f2fbff url(../assets/stylesheet/gradient-promo.png) repeat-x scroll 0 0;
+ border: 2px solid #fff;
+ -moz-border-radius: 10px;
+ -webkit-border-radius: 10px;
+ border-radius: 10px;
+ margin: 0;
+ padding: 0;
+ font-size: 13px;
+}
+.yui3-overlay fieldset {
+ border: 1px solid #cde;
+ -moz-border-radius: 10px;
+ -webkit-border-radius: 10px;
+ border-radius: 10px;
+ margin: 0;
+ padding: 20px;
+}
+.yui3-overlay h3 {
+ border-bottom: 2px solid #fff;
+ color: #479;
+ background: transparent;
+ margin: 0;
+ font-size: 175%;
+}
+.yui3-overlay label {
+ display: block;
+ margin: 1.3em 0 0.5ex;
+ font-weight: bold;
+ color: #003;
+}
+.yui3-overlay p {
+ margin: 2em 0 0;
+}
+/* override the move cursor for the Slider */
+.yui3-overlay .yui3-slider:hover {
+ cursor: default;
+}
+</style>
+
+
+