Css 如何在画布上放置div

Css 如何在画布上放置div,css,html,canvas,Css,Html,Canvas,我有以下html: <body> <input id="slider" type="range" min="0" max="100" step="1"></input> <div id="backward" class="button"></div> <canvas id="canvas" width="800" height="500" style="border: 1px solid;"><

我有以下html:

<body>
    <input id="slider" type="range" min="0" max="100" step="1"></input>
    <div id="backward" class="button"></div>
    <canvas id="canvas" width="800" height="500" style="border: 1px solid;"></canvas>
    <div id="forward" class="button"></div>
</body>

我还需要什么样的css才能将backward div放在canvas元素的左侧,将forward div放在canvas元素的右侧?

放在左侧?在右边吗?这是什么意思?这对我来说很好:
#canvas{
    position: absolute;
    left: 0px;
    top: 0px;
    z-index: 50;
}

.button{
    position: absolute;
    top: 10px;
    z-index: 100;
}