博客美化，页首波浪

首先需要申请开通博客js权限

接着在页首html栏添加如下代码即可

<canvas id="canvas" style="position:absolute;top:0px;left:0px;z-index:1;"></canvas>
<script type="text/javascript">
 var canvas = document.getElementById('canvas'); 
 var ctx = canvas.getContext('2d'); 
 canvas.width = canvas.parentNode.offsetWidth; 
 canvas.height = canvas.parentNode.offsetHeight;
 //如果浏览器支持requestAnimFrame则使用requestAnimFrame否则使用setTimeout 
 window.requestAnimFrame = (function(){ 
 return window.requestAnimationFrame  || 
   window.webkitRequestAnimationFrame || 
   window.mozRequestAnimationFrame || 
   function( callback ){ 
    window.setTimeout(callback, 1000 / 60); 
   }; 
 })(); 
 // 波浪大小
 var boHeight = canvas.height / 10;
 var posHeight = canvas.height / 1.2;
 //初始角度为0 
 var step = 0; 
 //定义三条不同波浪的颜色 
 var lines = ["rgba(0,222,255, 0.2)", 
     "rgba(157,192,249, 0.2)", 
     "rgba(0,168,255, 0.2)"]; 
 function loop(){ 
  ctx.clearRect(0,0,canvas.width,canvas.height); 
  step++; 
  //画3个不同颜色的矩形 
  for(var j = lines.length - 1; j >= 0; j--) { 
   ctx.fillStyle = lines[j]; 
   //每个矩形的角度都不同，每个之间相差45度 
   var angle = (step+j*50)*Math.PI/180; 
   var deltaHeight = Math.sin(angle) * boHeight;
   var deltaHeightRight = Math.cos(angle) * boHeight; 
   ctx.beginPath();
   ctx.moveTo(0, posHeight+deltaHeight); 
   ctx.bezierCurveTo(canvas.width/2, posHeight+deltaHeight-boHeight, canvas.width / 2, posHeight+deltaHeightRight-boHeight, canvas.width, posHeight+deltaHeightRight); 
   ctx.lineTo(canvas.width, canvas.height); 
   ctx.lineTo(0, canvas.height); 
   ctx.lineTo(0, posHeight+deltaHeight); 
   ctx.closePath(); 
   ctx.fill(); 
  }
  requestAnimFrame(loop);
 } 
 loop(); 
</script>