JS绘制一个从一个div指向另一个div的箭头

Question

I have the following code:

<div id="parent">
  <div class="child" id="air1">Medium 1</div>
  <div class="child" id="glass">Medium 2</div>
  <div class="child" id="air2">Medium 1</div>
</div>

<style>
  #parent {
    background: #999;
    padding: 0px;
  }
  #glass {
    background: #666;
  }
  .child {
    background: #ccc;
    height: 200px;
    margin: 0px;
  }
</style>

I want to draw an arrow from #air1 into #glass using an svg. I added the following code into the div to draw an example arrow:

<svg width="300" height="100">

    <defs>
        <marker id="arrow" markerWidth="13" markerHeight="13" refx="2" refy="6" orient="auto">
            <path d="M2,2 L2,11 L10,6 L2,2" style="fill:red;" />
        </marker>
    </defs>

    <path d="M30,150 L100,50"
          style="stroke:red; stroke-width: 1.25px; fill: none;
                 marker-end: url(#arrow);"
    />

</svg>

I don't want the arrow pointed in a random direction though, I want it to point into #glass like this:

Also, how would I go about drawing a less steep arrow like this as well:

How can I do this?

Answer 1

You can achieve that by using positioning (inserting the svg into the first section and set it to position: absolute; ) and adjusting the offset of the path element. To make the arrow pointing down, just use a negative value for the second value of the path description attribute.

For more information see w3schools about path .

 #parent { background: #999; padding: 0px; } #glass { background: #666; } .child { background: #ccc; height: 200px; margin: 0px; position: relative; } svg { position: absolute; left: 0; } 

 <div id="parent"> <div class="child" id="air1">Medium 1 <svg width="400" height="200"> <defs> <marker id="arrow" markerWidth="13" markerHeight="13" refx="2" refy="6" orient="auto"> <path d="M2,2 L2,11 L10,6 L2,2" style="fill:red;" /> </marker> </defs> <path d="M-600,-10 L300,195" style="stroke:red; stroke-width: 1.25px; fill: none; marker-end: url(#arrow);" /> </svg> </div> <div class="child" id="glass">Medium 2</div> <div class="child" id="air2">Medium 1</div> </div>