I am unable to drag the sidebar left or right. I want to increase and decrease the sidebar when it is dragged to the right and the left. When I tried to increase or decrease the width of the sidebar, it remained the same. There were no changes happening in that.

var i = 0;
$('#dragbar').mousedown(function(e) {

  e.preventDefault();
  $('#mousestatus').html("mousedown" + i++);
  $(document).mousemove(function(e) {
    $('#position').html(e.pageX + ', ' + e.pageY);
    $('#sidebar').css("width", e.pageX + 2);
    $('#main').css("left", e.pageX + 2);
  })
  console.log("leaving mouseDown");
});
$(document).mouseup(function(e) {
  $('#clickevent').html('in another mouseUp event' + i++);
  $(document).unbind('mousemove');
});

#main {
  background-color: BurlyWood;
  float: right;
  position: absolute;
  top: 100px;
  bottom: 38px;
  right: 0;
  left: 200px;
}
#sidebar {
  background-color: IndianRed;
  width: 200px;
  float: left;
  position: absolute;
  top: 100px;
  bottom: 38px;
  overflow-y: hidden;
}
#footer {
  background-color: PaleGoldenRod;
  width: 100%;
  height: 38px;
  bottom: 0;
  position: absolute;
}
#header {
  background-color: wheat;
  width: 100%;
  height: 100px;
}
#dragbar {
  background-color: black;
  height: 100%;
  float: right;
  width: 3px;
  cursor: col-resize;
}

<script src=".1.1/jquery.min.js"></script>
<div id="header">
  header
  <span id="mousestatus"></span>
  <span id="clickevent"></span>
</div>
<div id="sidebar">
  <span id="position"></span>
  <div id="dragbar"></div>
  sidebar
</div>
<div id="main">
  main
</div>
<div id="footer">
  footer
</div>

I am unable to drag the sidebar left or right. I want to increase and decrease the sidebar when it is dragged to the right and the left. When I tried to increase or decrease the width of the sidebar, it remained the same. There were no changes happening in that.

var i = 0;
$('#dragbar').mousedown(function(e) {

  e.preventDefault();
  $('#mousestatus').html("mousedown" + i++);
  $(document).mousemove(function(e) {
    $('#position').html(e.pageX + ', ' + e.pageY);
    $('#sidebar').css("width", e.pageX + 2);
    $('#main').css("left", e.pageX + 2);
  })
  console.log("leaving mouseDown");
});
$(document).mouseup(function(e) {
  $('#clickevent').html('in another mouseUp event' + i++);
  $(document).unbind('mousemove');
});

#main {
  background-color: BurlyWood;
  float: right;
  position: absolute;
  top: 100px;
  bottom: 38px;
  right: 0;
  left: 200px;
}
#sidebar {
  background-color: IndianRed;
  width: 200px;
  float: left;
  position: absolute;
  top: 100px;
  bottom: 38px;
  overflow-y: hidden;
}
#footer {
  background-color: PaleGoldenRod;
  width: 100%;
  height: 38px;
  bottom: 0;
  position: absolute;
}
#header {
  background-color: wheat;
  width: 100%;
  height: 100px;
}
#dragbar {
  background-color: black;
  height: 100%;
  float: right;
  width: 3px;
  cursor: col-resize;
}

<script src="https://ajax.googleapis./ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="header">
  header
  <span id="mousestatus"></span>
  <span id="clickevent"></span>
</div>
<div id="sidebar">
  <span id="position"></span>
  <div id="dragbar"></div>
  sidebar
</div>
<div id="main">
  main
</div>
<div id="footer">
  footer
</div>

• javascript
• jquery
• html
• css

2 Answers 2

using js

let sidebar = document.querySelector(".sidebar");
let content = document.querySelector(".content");
let dragholder = document.querySelector(".dragholder");

function onMouseMove(e){
  sidebar.style.cssText = `width: ${ e.pageX }px`;
  content.style.cssText = `width: ${ window.innerWidth - e.pageX }px`;
}

function onMouseDown(e){
  document.addEventListener('mousemove',onMouseMove);
}

function onMouseUp(e){
  document.removeEventListener('mousemove',onMouseMove);
}

dragholder.addEventListener('mousedown', onMouseDown);
dragholder.addEventListener('mouseup', onMouseUp);
content.addEventListener('mouseup', onMouseUp);
document.addEventListener('mouseup', onMouseUp);

body{
    margin:0;
    padding:0;
}
.container{
    display:flex;
  }
  
  .sidebar{
    background: lightgreen;
    height: 100vh;
    width: 20%;
    position:relative;
  }
  
  .dragholder{
     position:absolute;
     height: 100px;
     width: 5px;
     background: blue;
    right:0;
    top:50%;
    transform: translate(-50%, -50%);
    border-radius: 80px;
  }
  
  .dragholder:hover{
    cursor: move;
  }
  
  .content{
    background:red;
    height:100vh;
    width: 80%;
  }

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Drag bar</title>
  <link rel="stylesheet" href="styles.css">
</head>
<body>
  <div class="container">
    <div class="sidebar">
      <div class="dragholder"></div>
    </div>
    <div class="content"></div>
  </div>
  <script src="./index.js"></script>
</body>
</html>

You have multiple issues with your script.

The #main div overlaps the #sidebar, so the very right edge of the sidebar is not visible, nor accessible by the mouse. So, your mousedown event does not trigger, because it never receives a mousedown.

Two things to do here:

Add z-index: 1 for #main and z-index: 2 for #sidebar.

Also, to make your drag handle div to fit correctly, change it's css to this:

#dragbar {
  background-color: black;
  height: 100%;
  width: 3px;
  cursor: col-resize;
  position: absolute;
  right: 0;
  top: 0;
}

See the snippet below for a working version:

var i = 0;
$('#dragbar').mousedown(function(e) {

  e.preventDefault();
  $('#mousestatus').html("mousedown" + i++);
  $(document).mousemove(function(e) {
    $('#position').html(e.pageX + ', ' + e.pageY);
    $('#sidebar').css("width", e.pageX + 2);
    $('#main').css("left", e.pageX + 2);
  })
  console.log("leaving mouseDown");
});
$(document).mouseup(function(e) {
  $('#clickevent').html('in another mouseUp event' + i++);
  $(document).unbind('mousemove');
});

#main {
  background-color: BurlyWood;
  float: right;
  position: absolute;
  top: 100px;
  bottom: 38px;
  right: 0;
  left: 200px;
  z-index: 1;
}
#sidebar {
  background-color: IndianRed;
  width: 200px;
  float: left;
  position: absolute;
  top: 100px;
  bottom: 38px;
  overflow-y: hidden;
  z-index: 2;
}
#footer {
  background-color: PaleGoldenRod;
  width: 100%;
  height: 38px;
  bottom: 0;
  position: absolute;
}
#header {
  background-color: wheat;
  width: 100%;
  height: 100px;
}
#dragbar {
  background-color: black;
  height: 100%;
  width: 3px;
  cursor: col-resize;
  position: absolute;
  right: 0;
  top: 0;
}

<script src="https://ajax.googleapis./ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="header">
  header
  <span id="mousestatus"></span>
  <span id="clickevent"></span>
</div>
<div id="sidebar">
  <span id="position"></span>
  <div id="dragbar"></div>
  sidebar
</div>
<div id="main">
  main
</div>
<div id="footer">
  footer
</div>