HTML5计时器小例子

2014-07-23来源：易贤网

html:

代码如下:

<!DOCTYPE html>

<head>

<!-- Always force latest IE rendering engine (even in intranet) & Chrome Frame

Remove this if you use the .htaccess -->

<title>HTML5 Timer for work-relax balance</title>

countDownSeconds = 60;

var handle = null;

//window load

function onLoadWindow() {

aCanvas = document.getElementById("countdownCanvas");

context = aCanvas.getContext("2d");

var canvasText = "Press to Start...";

var xPos = aCanvas.width / 2;

var yPos = aCanvas.height / 2;

context.font = "12pt Century Gothic";

context.fillStyle = "#008000;";

context.textAlign = "center";

context.textBaseline = "middle";

context.fillText(canvasText, xPos, yPos);

}

function updateCanvas(theContext, width, height) {

if (countDownSeconds < 0) {

clearInterval(handle);

handle = null;

alert("hey, time is up!");

return 0;

}

minStr = Math.floor(countDownSeconds / 60);

secStr = countDownSeconds % 60;

if (minStr < 10) {

minStr = "0" + minStr;

}

if (secStr < 10) {

secStr = "0" + secStr;

}

context.clearRect(0, 0, width, height);

context.font = "24pt Century Gothic";

context.fillText(minStr + " : " + secStr, width / 2, height / 2);

countDownSeconds--;

}

function startWorkCountDown() {

if (handle != null) {

clearInterval(handle);

}

countDownSeconds = document.getElementById("workIntervalInput").value * 60;

timeDisplayCanvas = document.getElementById("countdownCanvas");

timeDisplayContext2D = timeDisplayCanvas.getContext("2d");

updateCanvas(timeDisplayContext2D, timeDisplayCanvas.width, timeDisplayCanvas.height);

handle = setInterval(function() {

updateCanvas(timeDisplayContext2D, timeDisplayCanvas.width, timeDisplayCanvas.height);

}, 1000);

}

function startRestCountDown() {

if (handle != null) {

clearInterval(handle);

}

countDownSeconds = document.getElementById("restIntervalInput").value * 60;

timeDisplayCanvas = document.getElementById("countdownCanvas");

timeDisplayContext2D = timeDisplayCanvas.getContext("2d");

updateCanvas(timeDisplayContext2D, timeDisplayCanvas.width, timeDisplayCanvas.height);

handle = setInterval(function() {

updateCanvas(timeDisplayContext2D, timeDisplayCanvas.width, timeDisplayCanvas.height);

}, 1000);

}

</script>

</head>

<h1>work-life balance timer</h1>

</header>

Please choose the work interval:

minutes

Please choose the rest interval:

minutes

This is a canvas

</canvas>

Work Hard

</button>

Take A Break

</button>

<p>

</p>

</footer>

</div>

</body>

</html>

css3:

代码如下:

* HTML5 ✰ Boilerplate

* What follows is the result of much research on cross-browser styling.

* Credit left inline and big thanks to Nicolas Gallagher, Jonathan Neal,

* Kroc Camen, and the H5BP dev community and team.

* Detailed information about this CSS: h5bp.com/css

* ==|== normalize ==========================================================

/* =============================================================================

HTML5 display definitions

========================================================================== */

article, aside, details, figcaption, figure, footer, header, hgroup, nav, section { display: block; }

header {text-shadow: #220000 0px 0px 10px 10px;}

audio, canvas, video { display: inline-block; *display: inline; *zoom: 1; }

audio:not([controls]) { display: none; }

[hidden] { display: none; }

/* =============================================================================

Base

========================================================================== */

* 1. Correct text resizing oddly in IE6/7 when body font-size is set using em units

* 2. Force vertical scrollbar in non-IE

* 3. Prevent iOS text size adjust on device orientation change, without disabling user zoom: h5bp.com/g

html { font-size: 100%; overflow-y: scroll; -webkit-text-size-adjust: 100%; -ms-text-size-adjust: 100%; }

body { margin: 0; font-size: 24px; line-height: 1.231;}

body, button, input, select, textarea {font-family:"Century Gothic"; color:#008000}

* Remove text-shadow in selection highlight: h5bp.com/i

* These selection declarations have to be separate

* Also: hot pink! (or customize the background color to match your design)

::-moz-selection { background: #fe57a1; color: #fff; text-shadow: none; }

::selection { background: #fe57a1; color: #fff; text-shadow: none; }

/* =============================================================================

Links

========================================================================== */

a { color: #00e; }

a:visited { color: #551a8b; }

a:hover { color: #06e; }

a:focus { outline: thin dotted; }

/* Improve readability when focused and hovered in all browsers: h5bp.com/h */

a:hover, a:active { outline: 0; }

/* =============================================================================

Typography

========================================================================== */

abbr[title] { border-bottom: 1px dotted; }

b, strong { font-weight: bold; }

blockquote { margin: 1em 40px; }

dfn { font-style: italic; }

hr { display: block; height: 1px; border: 0; border-top: 1px solid #ccc; margin: 1em 0; padding: 0; }

ins { background: #ff9; color: #000; text-decoration: none; }

mark { background: #ff0; color: #000; font-style: italic; font-weight: bold; }

/* Redeclare monospace font family: h5bp.com/j */

pre, code, kbd, samp { font-family: monospace, monospace; _font-family: 'courier new', monospace; font-size: 1em; }

/* Improve readability of pre-formatted text in all browsers */

pre { white-space: pre; white-space: pre-wrap; word-wrap: break-word; }

q { quotes: none; }

q:before, q:after { content: ""; content: none; }

small { font-size: 85%; }

/* Position subscript and superscript content without affecting line-height: h5bp.com/k */

sub, sup { font-size: 75%; line-height: 0; position: relative; vertical-align: baseline; }

sup { top: -0.5em; }

sub { bottom: -0.25em; }

/* =============================================================================

Lists

========================================================================== */

ul, ol { margin: 1em 0; padding: 0 0 0 40px; }

dd { margin: 0 0 0 40px; }

nav ul, nav ol { list-style: none; list-style-image: none; margin: 0; padding: 0; }

/* =============================================================================

Embedded content

========================================================================== */

* 1. Improve image quality when scaled in IE7: h5bp.com/d

* 2. Remove the gap between images and borders on image containers: h5bp.com/e

img { border: 0; -ms-interpolation-mode: bicubic; vertical-align: middle; }

* Correct overflow not hidden in IE9

svg:not(:root) { overflow: hidden; }

/* =============================================================================

Figures

========================================================================== */

figure { margin: 0; }

/* =============================================================================

Forms

========================================================================== */

form { margin: 0; }

fieldset { border: 0; margin: 0; padding: 0; }

/* Indicate that 'label' will shift focus to the associated form element */

label { cursor: pointer; }

* 1. Correct color not inheriting in IE6/7/8/9

* 2. Correct alignment displayed oddly in IE6/7

legend { border: 0; *margin-left: -7px; padding: 0; }

* 1. Correct font-size not inheriting in all browsers

* 2. Remove margins in FF3/4 S5 Chrome

* 3. Define consistent vertical alignment display in all browsers

button, input, select, textarea { font-size: 100%; margin: 0; vertical-align: baseline; *vertical-align: middle; }

* 1. Define line-height as normal to match FF3/4 (set using !important in the UA stylesheet)

* 2. Correct inner spacing displayed oddly in IE6/7

button, input { line-height: normal; *overflow: visible; }

* Reintroduce inner spacing in 'table' to avoid overlap and whitespace issues in IE6/7

table button, table input { *overflow: auto; }

* 1. Display hand cursor for clickable form elements

* 2. Allow styling of clickable form elements in iOS

button, input[type="button"], input[type="reset"], input[type="submit"] { cursor: pointer; -webkit-appearance: button; }

* Consistent box sizing and appearance

input[type="checkbox"], input[type="radio"] { box-sizing: border-box; }

input[type="search"] { -webkit-appearance: textfield; -moz-box-sizing: content-box; -webkit-box-sizing: content-box; box-sizing: content-box; }

input[type="search"]::-webkit-search-decoration { -webkit-appearance: none; }

* Remove inner padding and border in FF3/4: h5bp.com/l

button::-moz-focus-inner, input::-moz-focus-inner { border: 0; padding: 0; }

* 1. Remove default vertical scrollbar in IE6/7/8/9

* 2. Allow only vertical resizing

textarea { overflow: auto; vertical-align: top; resize: vertical; }

/* Colors for form validity */

input:valid, textarea:valid { }

input:invalid, textarea:invalid { background-color: #f0dddd; }

/* =============================================================================

Tables

========================================================================== */

table { border-collapse: collapse; border-spacing: 0; }

td { vertical-align: top; }

/* ==|== primary styles =====================================================

Author:

========================================================================== */

/* ==|== non-semantic helper classes ========================================

Please define your styles before this section.

========================================================================== */

/* For image replacement */

.ir { display: block; border: 0; text-indent: -999em; overflow: hidden; background-color: transparent; background-repeat: no-repeat; text-align: left; direction: ltr; }

.ir br { display: none; }

/* Hide from both screenreaders and browsers: h5bp.com/u */

.hidden { display: none !important; visibility: hidden; }

/* Hide only visually, but have it available for screenreaders: h5bp.com/v */

.visuallyhidden { border: 0; clip: rect(0 0 0 0); height: 1px; margin: -1px; overflow: hidden; padding: 0; position: absolute; width: 1px; }

/* Extends the .visuallyhidden class to allow the element to be focusable when navigated to via the keyboard: h5bp.com/p */

.visuallyhidden.focusable:active, .visuallyhidden.focusable:focus { clip: auto; height: auto; margin: 0; overflow: visible; position: static; width: auto; }

/* Hide visually and from screenreaders, but maintain layout */

.invisible { visibility: hidden; }

/* Contain floats: h5bp.com/q */

.clearfix:before, .clearfix:after { content: ""; display: table; }

.clearfix:after { clear: both; }

.clearfix { zoom: 1; }

/* ==|== media queries ======================================================

PLACEHOLDER Media Queries for Responsive Design.

These override the primary ('mobile first') styles

Modify as content requires.

========================================================================== */

@media only screen and (min-width: 480px) {

/* Style adjustments for viewports 480px and over go here */

}

@media only screen and (min-width: 768px) {

/* Style adjustments for viewports 768px and over go here */

}

/* ==|== print styles =======================================================

Print styles.

Inlined to avoid required HTTP connection: h5bp.com/r

========================================================================== */

@media print {

* { background: transparent !important; color: black !important; text-shadow: none !important; filter:none !important; -ms-filter: none !important; } /* Black prints faster: h5bp.com/s */

a, a:visited { text-decoration: underline; }

a[href]:after { content: " (" attr(href) ")"; }

abbr[title]:after { content: " (" attr(title) ")"; }

.ir a:after, a[href^="javascript:"]:after, a[href^="#"]:after { content: ""; } /* Don't show links for images, or javascript/internal links */

pre, blockquote { border: 1px solid #999; page-break-inside: avoid; }

thead { display: table-header-group; } /* h5bp.com/t */

tr, img { page-break-inside: avoid; }

img { max-width: 100% !important; }

@page { margin: 0.5cm; }

p, h2, h3 { orphans: 3; widows: 3; }

h2, h3 { page-break-after: avoid; }

}