What is Selenese ?

Selenese is language used to write script generated by using selenium ide, it can be in multiple languages java,python etc.
Selenese is the set of commands which is used in Selenium IDE. Selenese a sequence of these commands help us to run our tests in a group creates 'test script',
These set of commands are used to testing your web applications, to check the existence of specific elements on web page,
any window or pop up, presence of broken links on the web page, any alert box, any Ajax functionality, window, list options and many more of web applications.

 Selenium commands, often called selenese, Selenese html is the html file of selenium ide used for selenium files and commands.
 
to run our tests
to check the presence of broken link on web page
to check the existence of specific elements on web page
to verify any window or pop up or any alert box
for any Ajax functionality and etc

And the Selenium commands are grouped classified into 3 different categories:

Action Commands: which is used to change the state of the application are classified as Actions. It does things like type a value in edit box, "click this link" and “select that option”, select a value from drop down etc. If an Action fails or has an error, the execution of the current test is stopped.
Accessors Command: checks the state of the application and stores the application state in some variable, (e.g storeTitle,storeElementPresent). They are also used to automatically generate Assertions.
Assertions commands: are used like the checkpoints or verification points in automation. It verifies the state of application conforms to an expected state and generates the True/False result, e.g such as verifyText, verifyTitle, assertText etc.

Now the Selenium Assertions can also be categorized into three category:

They will succeed immediately if the condition is already true.

waitFor: Wait for some condition to become true.
assert: When an 'Assert' fails, the test is aborted.
verify: When a 'Verify' fails, the test will continue execution, logging the failures.

However, they will fail and halt the test if the condition does not become true within the current timeout setting.