HTML5超炫酷粒子效果的进度条的实现示例

这是一款基于html5和javascript的进度条应用，这款进度条插件非常有特点，它在进度展示的时候呈现粒子的动画效果，也就是说，进度条在滑动的同时，会产生一些小粒子掉落下来，效果非常酷。另外还有一个特点是随着进度的变化，进度条的颜色也会变化。

javascript代码

/*========================================================*/  /* 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;      /*========================================================智慧树教育*/        /* 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;        } el {            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+'招商工作总结, 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.update克制的意思particles = 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'));};/*========================================================*/    /* tup requestanimationframe/*========================================================*/var tupraf = 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.ttimeout(function() { callback(currtime + timetocall); }, timetocall);            lasttime = currtime + timetocall;            return id;        };    };    if (!window.cancelanimationframe){        window.cancelanimationframe = function(id){            cleartimeout(id);        };    };};          /*========================================================*/    /* define canvas and initialize/*=========================商家最怕哪个部门投诉===============================*/if(iscanvassupported){  var c = document.createelement('canvas');  c.width = 400;  c.height = 100;             var cw = c.width;  var ch = c.薛之谦 安河桥height;      document.body.appendchild(c);   var cl = new lightloader(c, cw, ch);                tupraf();  cl.init();}

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