JSFiddle - React, Tailwind, and code Playground

by aybalasubramanian

HTML

<div id="div1" style="position:absolute; background-color:blue; width:100px; height: 200px;top: 200px; left: 100px;">
&nbsp;
</div>
<br/><br/>
<div id="div2" style="position:absolute; background-color:red; width:100px; height: 200px; top: 300px; left: 300px;">
&nbsp;
</div>
<input type="button" onclick="testIt();" value="Draw Line" />

JavaScript

function connect(div1, div2, color, thickness) {
    var off1 = getOffset(div1);
    var off2 = getOffset(div2);
    // bottom right
    var x1 = off1.left + off1.width;
    var y1 = off1.top + off1.height;
    // top right
    var x2 = off2.left + off2.width;
    var y2 = off2.top;
    // distance
    var length = Math.sqrt(((x2-x1) * (x2-x1)) + ((y2-y1) * (y2-y1)));
    // center
    var cx = ((x1 + x2) / 2) - (length / 2);
    var cy = ((y1 + y2) / 2) - (thickness / 2);
    // angle
    var angle = Math.atan2((y1-y2),(x1-x2))*(180/Math.PI);
    // make hr
    var htmlLine = "<div style='padding:0px; margin:0px; height:" + thickness + "px; background-color:" + color + "; line-height:1px; position:absolute; left:" + cx + "px; top:" + cy + "px; width:" + length + "px; -moz-transform:rotate(" + angle + "deg); -webkit-transform:rotate(" + angle + "deg); -o-transform:rotate(" + angle + "deg); -ms-transform:rotate(" + angle + "deg); transform:rotate(" + angle + "deg);' />";
    //
    //alert(htmlLine);
    document.body.innerHTML += htmlLine; 
}

function getOffset( el ) {
    var rect = el.getBoundingClientRect();
    return {
        left: rect.left + window.pageXOffset,
        top: rect.top + window.pageYOffset,
        width: rect.width || el.offsetWidth,
        height: rect.height || el.offsetHeight
    };
}

window.testIt = function() {
    var div1 = document.getElementById('div1');
    var div2 = document.getElementById('div2')
    connect(div1, div2, "#0F0", 5);
}