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tags: English
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# SideeX TAC Auto-Locator
## The Locator Decay Problem
Web element locators, such as XPaths and CSS Selectors, are widely used to locate web elements in HTML web pages and serve as building blocks in developing automated functional web testing software tools. However, as the contents of web pages evolve over time, web elements may change on their texts, attributes or locations. A well-known case is the random id situation where elements are randomly assigned with random ids after each page reload. As a result, a web element locator may decay, which means it cannot continue to correctly identify the original element over the revisions of the web page. Hence, the tool user has to manually fix the locator by selecting another locator or creating a new one, which result in a high cost of maintaining the fragile test cases.

## TAC Auto-Locator
To solve the locator decay problem, we propose a new locator, called **TAC Auto-Locator**. It is a highly intelligent and robust locator (more specifically is a complex algorithm), which can automatically identify a recorded web element over the web page revisions with high precision and efficiency, largely reducing the need of the manual selection among a number of locators.

## How to Use TAC Auto-Locator on SideeX Recorder

1. Enable TAC auto-locator on Option page 
2. By default, TAC auto-locator is preset as the most preferred locator.
3. Start recording your test cases. The targets of the recorded commands will display **`TAC(Some text you can edit)`**.
4. While playing the test cases, TAC auto-locator will automatically find these elements.

## An Example

1. Open [the Samsung website in 2017](http://web.archive.org/web/20170804001525/http://www.samsung.com/us/) on Wayback Machine Internet Archive.
2. Start recording mode of SideeX.
3. After clicking the *LOG IN / SIGN UP* button, the drop down menu will display as the following screenshot.
4. Two commands will be recorded. The target element of the *clickAt* command will display TAC(LOG IN / SIG...).
5. Change the *open* command's target to [the new website in 2019](http://web.archive.org/web/20191123072248/https://www.samsung.com/us/).
6. Running the test case again. TAC auto-locator will successfully find the *LOG IN / SIGN UP* element on the new page even though the element has changed its looks. See the following snapshot.

## Parameter free, pre-training free, and high precision
SideeX TAC Auto-Locator was designed to serve as an easy-to-use locator. No need to elaborate a set of arguments nor to train any models beforehand. Just record and replay your test cases, all recorded elements will automatically be located.