add explicitly wait in selenium code example

Example 1: explicit wait in selenium

2- Explicit Wait
explicit is waiting for
explicit condition to happen
Like:
-elementIsDisplayed
-titleIs()
-visibilityOf
-elementToBeClickable

We need to create object from 
webdriverwait class

Example 2: implicit wait vs explicit wait

In Implicit wait, if WebDriver is not able to
locate an element, it will wait for a specified
amount of time for the element to appear, 
before throwing an exception.

Explicit wait is a type of wait , which is used to
stop the execution till a specific condition is true;
We use WebDriverWait and ExpectedCondition classes of
Selenium web driver to implement explicit wait.
Implicit wait is general, explicit wait is applied
for a particular instance only.



WebDriverWait wait = new WebDriverWait(driver, 10);
wait.until(ExpectedConditions.elementToBeClickable(txtFirstname));