
具体代码如下:
实现思路:HTML里只需要一个CANVAS元素,Javascript里操作canvas
1、给canvas里绘制背景图片
2、在绘制半径为0-10px的圆形,x坐标屏幕水平随机,y所标竖直大于屏幕高度。
圆形背景色可以是随机,那就是各种色彩了!
利用计时器控制y--
构建html
<!doctype html><html lang="en"> <head> <meta charset="UTF-8"> <meta name="Generator" content="EditPlus®"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <title>5多个小球往上运动</title> <style> </style> </head> <body><div id="d1"><canvas id="canvas"></canvas></div> </body></html>js代码
<script>var canvas=document.getElementById("canvas");var context=canvas.getContext("2d");canvas.width=window.innerWidth;canvas.height=window.innerHeight;function Circle(){this.x=Math.random()*canvas.width;this.y=canvas.height;this.r=Math.random()*10;//绘制圆形this.paint=function(){context.beginPath();context.arc(this.x,this.y,this.r,0,Math.PI*2);context.fillStyle="white";context.globalAlpha = 0.5;context.fill();}//控制圆形移动this.step=function(){this.y--;}}var circles=[];function createCircles(){var circle=new Circle();//??????circles[circles.length]=circle;} function paintCircles(){for(var i=0;i<circles.length;i++){circles[i].paint();}}function stepCircles(){for(var i=0;i<circles.length;i++){circles[i].step();}}var myimg=new Image();myimg.src="images/demo-1.png";var timer="";setInterval(function(){context.drawImage(myimg,0,0);timer++;if(timer%20==0){createCircles();}paintCircles();stepCircles();},10);</script>需要在自己的网站中添加浪漫元素,这不失为一种好的方式,希望大家灵活运用javascript实现气泡冒出特效,谢谢大家的阅读。