**An efficient blocker add-on for various browsers. Fast, potent, and lean.** [<imgsrc="https://travis-ci.org/chrisaljoudi/uBlock.svg?branch=master"height="12">](https://travis-ci.org/chrisaljoudi/uBlock)
uBlock is not an *ad blocker*; it's a general-purpose blocker. uBlock blocks ads through its support of the [Adblock Plus filter syntax](https://adblockplus.org/en/filters). uBlock [extends](https://github.com/chrisaljoudi/uBlock/wiki/Filter-syntax-extensions) the syntax and is designed to work with custom rules and filters.
That said, it's important to note that using a blocker is **NOT** [theft](https://twitter.com/LeaVerou/status/518154828166725632). Don't fall for this creepy idea. The _ultimate_ logical consequence of `blocking = theft` is the criminalisation of the inalienable right to privacy.
Ads, "unintrusive" or not, are just the visible portions of privacy-invading apparatus entering your browser when you visit most sites nowadays. **uBlock's main goal is to help users neutralize such privacy-invading apparatus** — in a way that welcomes those users who don't wish to use more technical, involved means (such as [µMatrix](https://github.com/chrisaljoudi/uMatrix)).
For advanced usage, read about [dynamic filtering](https://github.com/chrisaljoudi/uBlock/wiki/Dynamic-filtering:-quick-guide) and more on [uBlock's wiki](https://github.com/chrisaljoudi/uBlock/wiki).
<sup>[1] Details of the benchmark available at <ahref="https://github.com/chrisaljoudi/uBlock/wiki/Firefox-version:-benchmarking-memory-footprint">Firefox version: benchmarking memory footprint</a>.</sup><br>
<sup>[2] Important note: There is currently a [bug in Chromium 39+ which causes a new memory leak each time the popup UI of an extension is opened](https://code.google.com/p/chromium/issues/detail?id=441500). This affects <i>all</i> extensions. Keep this in mind when measuring Chromium's memory usage. In the benchmarks, I avoided opening the popups completely.</sup><br>
<sup>Details of the benchmark available in <ahref="https://github.com/chrisaljoudi/uBlock/blob/master/doc/benchmarks/cpu-usage-overall-20141226.ods">this LibreOffice spreadsheet</a>.</sup>
_EasyList_, _Peter Lowe's Adservers_, _EasyPrivacy_ and _Malware domains_ are enabled by default when you install uBlock. Many more lists are readily available to block trackers, analytics, and more. Hosts files are also supported.
Once you install uBlock, you can easily un-select any of the pre-selected filter lists if you think uBlock blocks too much. For reference, Adblock Plus installs with only _EasyList_ enabled by default.
**To benefit from uBlock's higher efficiency,** it's advised that you don't use other inefficient blockers at the same time (such as AdBlock or Adblock Plus). uBlock will do [as well or better](#blocking) than most popular ad blockers.
You can install the latest version from the [Chrome Web Store](https://chrome.google.com/webstore/detail/ublock/epcnnfbjfcgphgdmggkamkmgojdagdnn), from the [Opera store](https://addons.opera.com/en-gb/extensions/details/ublock/), or [manually](https://github.com/chrisaljoudi/uBlock/tree/master/dist#install).
Install from [Firefox Add-ons homepage](https://addons.mozilla.org/en-US/firefox/addon/ublock/), or you can install by downloading the latest [uBlock.firefox.xpi](https://github.com/chrisaljoudi/uBlock/releases) file, and by dragging the downloaded `xpi` file to your add-on page.
<sup>**Note:** When a new version is submitted at _Mozilla Add-ons_ (AMO), it takes **weeks** for that submission to be reviewed and cleared. Any new submission would cancel the pending one, and the new one would be placed at the end of the reviewing queue. So that the version on AMO is way behind the latest release here is completely out of control of the developers.</sup>
Install the latest uBlock for Safari [from its homepage](https://chrismatic.io/ublock/), or a potentially-outdated version from the [Safari Extension Gallery](https://extensions.apple.com/details/?id=net.chrisaljoudi.uBlock-96G4BAKDQ9).
