HTML5进度条特效_html5教程技巧

代码如下:

/*==============================================*/
/* Light Loader
/*==================================================*/
var lightLoader = function (c, cw, ch) {
var _this = this;
this.c = c;
this.ctx = c.getContext('2d');
this.cw = cw;
this.ch = ch;
this.loaded = 0;
this.loaderSpeed = .6;
this.loaderHeight = 10;
this.loaderWidth = 310;
this.loader = {
x: (this.cw / 2) - (this.loaderWidth / 2),
y: (this.ch / 2) - (this.loaderHeight / 2)
};
this.particles = [];
this.particleLift = 180;
this.hueStart = 0
this.hueEnd = 120;
this.hue = 0;
this.gravity = .15;
this.particleRate = 4;
/*========================================================*/
/* Initialize
/*========================================================*/
this.init = function () {
this.loop();
};
/*========================================================*/
/* Utility Functions
/*========================================================*/
this.rand = function (rMi, rMa) { return ~ ~((Math.random() * (rMa - rMi + 1)) + rMi); };
this.hitTest = function (x1, y1, w1, h1, x2, y2, w2, h2) { return !(x1 + w1 < x2 || x2 + w2 < x1 || y1 + h1 < y2 || y2 + h2 < y1); };
/*========================================================*/
/* Update Loader
/*========================================================*/
this.updateLoader = function () {
if (this.loaded < 100) {
this.loaded += this.loaderSpeed;
} else {
this.loaded = 0;
}
};
/*========================================================*/
/* Render Loader
/*========================================================*/
this.renderLoader = function () {
this.ctx.fillStyle = '#000';
this.ctx.fillRect(this.loader.x, this.loader.y, this.loaderWidth, this.loaderHeight);
this.hue = this.hueStart + (this.loaded / 100) * (this.hueEnd - this.hueStart);
var newWidth = (this.loaded / 100) * this.loaderWidth;
this.ctx.fillStyle = 'hsla(' + this.hue + ', 100%, 40%, 1)';
this.ctx.fillRect(this.loader.x, this.loader.y, newWidth, this.loaderHeight);
this.ctx.fillStyle = '#222';
this.ctx.fillRect(this.loader.x, this.loader.y, newWidth, this.loaderHeight / 2);
};
/*========================================================*/
/* Particles
/*========================================================*/
this.Particle = function () {
this.x = _this.loader.x + ((_this.loaded / 100) * _this.loaderWidth) - _this.rand(0, 1);
this.y = _this.ch / 2 + _this.rand(0, _this.loaderHeight) - _this.loaderHeight / 2;
this.vx = (_this.rand(0, 4) - 2) / 100;
this.vy = (_this.rand(0, _this.particleLift) - _this.particleLift * 2) / 100;
this.width = _this.rand(1, 4) / 2;
this.height = _this.rand(1, 4) / 2;
this.hue = _this.hue;
};
this.Particle.prototype.update = function (i) {
this.vx += (_this.rand(0, 6) - 3) / 100;
this.vy += _this.gravity;
this.x += this.vx;
this.y += this.vy;
if (this.y > _this.ch) {
_this.particles.splice(i, 1);
}
};
this.Particle.prototype.render = function () {
_this.ctx.fillStyle = 'hsla(' + this.hue + ', 100%, ' + _this.rand(50, 70) + '%, ' + _this.rand(20, 100) / 100 + ')';
_this.ctx.fillRect(this.x, this.y, this.width, this.height);
};
this.createParticles = function () {
var i = this.particleRate;
while (i--) {
this.particles.push(new this.Particle());
};
};
this.updateParticles = function () {
var i = this.particles.length;
while (i--) {
var p = this.particles[i];
p.update(i);
};
};
this.renderParticles = function () {
var i = this.particles.length;
while (i--) {
var p = this.particles[i];
p.render();
};
};

/*========================================================*/
/* Clear Canvas
/*========================================================*/
this.clearCanvas = function () {
this.ctx.globalCompositeOperation = 'source-over';
this.ctx.clearRect(0, 0, this.cw, this.ch);
this.ctx.globalCompositeOperation = 'lighter';
};
/*========================================================*/
/* Animation Loop
/*========================================================*/
this.loop = function () {
var loopIt = function () {
requestAnimationFrame(loopIt, _this.c);
_this.clearCanvas();
_this.createParticles();
_this.updateLoader();
_this.updateParticles();
_this.renderLoader();
_this.renderParticles();
};
loopIt();
};
};
/*========================================================*/
/* Check Canvas Support
/*========================================================*/
var isCanvasSupported = function () {
var elem = document.createElement('canvas');
return !!(elem.getContext && elem.getContext('2d'));
};
/*========================================================*/
/* Setup requestAnimationFrame
/*========================================================*/
var setupRAF = function () {
var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
for (var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
window.cancelAnimationFrame = window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame'];
};
if (!window.requestAnimationFrame) {
window.requestAnimationFrame = function (callback, element) {
var currTime = new Date().getTime();
var timeToCall = Math.max(0, 16 - (currTime - lastTime));
var id = window.setTimeout(function () { callback(currTime + timeToCall); }, timeToCall);
lastTime = currTime + timeToCall;
return id;
};
};
if (!window.cancelAnimationFrame) {
window.cancelAnimationFrame = function (id) {
clearTimeout(id);
};
};
};
/*========================================================*/
/* Define Canvas and Initialize
/*========================================================*/
if (isCanvasSupported) {
var c = document.createElement('canvas');
c.width = 400;
c.height = 100;
var cw = c.width;
var ch = c.height;
document.body.appendChild(c);
var cl = new lightLoader(c, cw, ch);
setupRAF();
cl.init();
}

HTML5进度条
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