Question

我正在尝试将圣诞节Javascript叠加到网站上，我正在使用的标签显示在我的其他网站内容上。

      window.onload = function(){
      //canvas init
      var canvas = document.getElementById("canvas");
      var ctx = canvas.getContext("2d");
      
      //canvas dimensions
      var W = window.innerWidth;
      var H = window.innerHeight;
      canvas.width = W;
      canvas.height = H;
      
      //snowflake particles
      var mp = 25; //max particles
      var particles = [];
      for(var i = 0; i < mp; i++)
      {
        particles.push({
          x: Math.random()*W, //x-coordinate
          y: Math.random()*H, //y-coordinate
          r: Math.random()*4+1, //radius
          d: Math.random()*mp //density
        })
      }
      
      //Lets draw the flakes
      function draw()
      {
        ctx.clearRect(0, 0, W, H);
        
        ctx.fillStyle = "rgba(255, 255, 255, 0.8)";
        ctx.beginPath();
        for(var i = 0; i < mp; i++)
        {
          var p = particles[i];
          ctx.moveTo(p.x, p.y);
          ctx.arc(p.x, p.y, p.r, 0, Math.PI*2, true);
        }
        ctx.fill();
        update();
      }
      
      //Function to move the snowflakes
      //angle will be an ongoing incremental flag. Sin and Cos functions will be applied to it to create vertical and horizontal movements of the flakes
      var angle = 0;
      function update()
      {
        angle += 0.01;
        for(var i = 0; i < mp; i++)
        {
          var p = particles[i];
          //Updating X and Y coordinates
          //We will add 1 to the cos function to prevent negative values which will lead flakes to move upwards
          //Every particle has its own density which can be used to make the downward movement different for each flake
          //Lets make it more random by adding in the radius
          p.y += Math.cos(angle+p.d) + 1 + p.r/2;
          p.x += Math.sin(angle) * 2;
          
          //Sending flakes back from the top when it exits
          //Lets make it a bit more organic and let flakes enter from the left and right also.
          if(p.x > W+5 || p.x < -5 || p.y > H)
          {
            if(i%3 > 0) //66.67% of the flakes
            {
              particles[i] = {x: Math.random()*W, y: -10, r: p.r, d: p.d};
            }
            else
            {
              //If the flake is exitting from the right
              if(Math.sin(angle) > 0)
              {
                //Enter from the left
                particles[i] = {x: -5, y: Math.random()*H, r: p.r, d: p.d};
              }
              else
              {
                //Enter from the right
                particles[i] = {x: W+5, y: Math.random()*H, r: p.r, d: p.d};
              }
            }
          }
        }
      }
      
      //animation loop
      setInterval(draw, 33);
    }

    * {margin: 0; padding: 0;}
    
    body {
      /*You can use any kind of background here.*/
      background: #6b92b9;
    }
    canvas {
      display: block;
      position: absolute;
    }

    <canvas id="canvas">
    <header> <a href = "/games/"><img id="headerimg" src="http://hosted-it.co.uk/img/logo-colour.svg" alt="Hosted-IT" height="150px" width="250px" /> </a></header>
    
    <nav class="navbar"><form method="get" action="/games/questions">
        <button type="onclick">Questions</button>
    </form> </nav>
    <body>
    
    {% block content %}
    {% endblock %}
    
    </body>
    </canvas>

如果有帮助，这就是所有内联脚本/ html / css。它使用DJango模板使用主html文件来存储主格式，然后在各个文件中进行任何其他调整。我希望有人能帮助我弄清楚为什么画布标签完全覆盖页面本身的所有内容？

Answer 1

你应该提供一个plunker，但现在你可以尝试下面的css

canvas {
  display: block;
  position: relative;
}

将职位更改为“亲戚”。可能会起作用。并在第一行的HTML关闭画布标记

 <canvas id="canvas"></canvas>
   <header> <a href = "/games/"><img id="headerimg" src="http://hosted-it.co.uk/img/logo-colour.svg" alt="Hosted-IT" height="150px" width="250px" /></a></header>

    <nav class="navbar"><form method="get" action="/games/questions">
    <button type="onclick">Questions</button>
    </form> </nav>
    <body>

      {% block content %}
      {% endblock %}

    </body>

HTML Canvas显示在我的主要内容上

1 个答案: