3.9: Carousel interval example
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**Primary Actor**: User

**Scope**: Ngx-bootstrap DEMO / BS version 3&4

**Goal**: Show user carousel functionality with possibilities to change time interval

Main success scenario:
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1. User open Carousel demo page
2. User click on Interval sub-menu
3. User see carousel component with 3 slides and 2 arrows: left, right
4. User see input with default interval: 1500 milliseconds
5. When user change the interval in input to any positive value - then slides change after added interval
6. When user change the interval in input to "0" - then slider stopped
7. When user change the interval in input to any negative value - then carousel stopped

Variations:
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2*. User scroll to Interval sub-menu