Hide scroll bar, but while still being able to scroll

Just a test which is working fine.

#parent{
    width: 100%;
    height: 100%;
    overflow: hidden;
}

#child{
    width: 100%;
    height: 100%;
    overflow-y: scroll;
    padding-right: 17px; /* Increase/decrease this value for cross-browser compatibility */
    box-sizing: content-box; /* So the width will be 100% + 17px */
}

Working Fiddle

JavaScript:

Since the scrollbar width differs in different browsers, it is better to handle it with JavaScript. If you do Element.offsetWidth - Element.clientWidth, the exact scrollbar width will show up.

JavaScript Working Fiddle

Or

Using Position: absolute,

#parent{
    width: 100%;
    height: 100%;
    overflow: hidden;
    position: relative;
}

#child{
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: -17px; /* Increase/Decrease this value for cross-browser compatibility */
    overflow-y: scroll;
}

Working Fiddle

JavaScript Working Fiddle

Information:

Based on this answer, I created a simple scroll plugin.

It is easy in WebKit, with optional styling:

html {
    overflow: scroll;
    overflow-x: hidden;
}
::-webkit-scrollbar {
    width: 0;  /* Remove scrollbar space */
    background: transparent;  /* Optional: just make scrollbar invisible */
}
/* Optional: show position indicator in red */
::-webkit-scrollbar-thumb {
    background: #FF0000;
}

This works for me with simple CSS properties:

.container {
    -ms-overflow-style: none;  /* Internet Explorer 10+ */
    scrollbar-width: none;  /* Firefox */
}
.container::-webkit-scrollbar { 
    display: none;  /* Safari and Chrome */
}

For older versions of Firefox, use: overflow: -moz-scrollbars-none;

UPDATE:

Firefox now supports hiding scrollbars with CSS, so all major browsers are now covered (Chrome, Firefox, Internet Explorer, Safari, etc.).

Simply apply the following CSS to the element you want to remove scrollbars from:

.container {
    overflow-y: scroll;
    scrollbar-width: none; /* Firefox */
    -ms-overflow-style: none;  /* Internet Explorer 10+ */
}
.container::-webkit-scrollbar { /* WebKit */
    width: 0;
    height: 0;
}

This is the least hacky cross browser solution that I'm currently aware of. Check out the demo.

ORIGINAL ANSWER:

Here's another way that hasn't been mentioned yet. It's really simple and only involves two divs and CSS. No JavaScript or proprietary CSS is needed, and it works in all browsers. It doesn't require explicitly setting the width of the container either, thus making it fluid.

This method uses a negative margin to move the scrollbar out of the parent and then the same amount of padding to push the content back to its original position. The technique works for vertical, horizontal and two way scrolling.

Demos:

• Vertical
• Horizontal
• Both directions

Example code for the vertical version:

HTML:

<div class="parent">
  <div class="child">
    Your content.
  </div>
</div>

CSS:

.parent {
  width: 400px;
  height: 200px;
  border: 1px solid #AAA;
  overflow: hidden;
}

.child {
  height: 100%;
  margin-right: -50px; /* Maximum width of scrollbar */
  padding-right: 50px; /* Maximum width of scrollbar */
  overflow-y: scroll;
}

Use:

<div style='overflow:hidden; width:500px;'>
   <div style='overflow:scroll; width:508px'>
      My scroll-able area
   </div>
</div>

This is a trick to somewhat overlap the scrollbar with an overlapping div which doesn't have any scroll bars:

::-webkit-scrollbar {
    display: none;
}

This is only for WebKit browsers... Or you could use browser-specific CSS content (if there is any in future). Every browser could have a different and specific property for their respective bars.

For Microsoft Edge use: -ms-overflow-style: -ms-autohiding-scrollbar; or -ms-overflow-style: none; as per MSDN.

There is no equivalent for Firefox. Although there is a jQuery plugin to achieve this, http://manos.malihu.gr/tuts/jquery_custom_scrollbar.html