html5计时器小例子

2016-06-23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; }

}