js特效

代码结构

1. HTML代码

<canvas id="canvas" width="500" height="500" >cccc</canvas>
<script>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.strokeStyle = '#00ffff';
ctx.lineWidth = 17;
ctx.shadowBlur = 15;
ctx.shadowColor = '#00ffff'
function degToRad(degree) {
    var factor = Math.PI / 180;
    return degree * factor;
}
function renderTime() {
    var now = new Date();
    var today = now.toDateString();
    var time = now.toLocaleTimeString();
    var hrs = now.getHours();
    var min = now.getMinutes();
    var sec = now.getSeconds();
    var mil = now.getMilliseconds();
    var smoothsec = sec + (mil / 1000);
    var smoothmin = min + (smoothsec / 60);
    //Background
    gradient = ctx.createRadialGradient(250, 250, 5, 250, 250, 300);
    gradient.addColorStop(0, "#03303a");
    gradient.addColorStop(1, "black");
    ctx.fillStyle = gradient;
    //ctx.fillStyle = 'rgba(00 ,00 , 00, 1)';
    ctx.fillRect(0, 0, 500, 500);
    //Hours
    ctx.beginPath();
    ctx.arc(250, 250, 200, degToRad(270), degToRad((hrs * 30) - 90));
    ctx.stroke();
    //Minutes
    ctx.beginPath();
    ctx.arc(250, 250, 170, degToRad(270), degToRad((smoothmin * 6) - 90));
    ctx.stroke();
    //Seconds
    ctx.beginPath();
    ctx.arc(250, 250, 140, degToRad(270), degToRad((smoothsec * 6) - 90));
    ctx.stroke();
    //Date
    ctx.font = "25px Helvetica";
    ctx.fillStyle = 'rgba(00, 255, 255, 1)'
    ctx.fillText(today, 175, 250);
    //Time
    ctx.font = "25px Helvetica Bold";
    ctx.fillStyle = 'rgba(00, 255, 255, 1)';
    ctx.fillText(time + ":" + mil, 175, 280);
}
setInterval(renderTime, 40);</script>