When to use this Component
Use page alerts to bring the user’s attention to important page information or system status
Use page alerts to communicate the result of a user action (for example, error or success)
When not to use this Component
Do not use page alerts just for styling regular content (for emphasis or highlighting)
Do not use page alerts to provide information about a normal step in a process or task
Do not use page alerts to tell the user about a problem that’s affecting the service as a whole – Use product alerts instead
Best Practices
Do
Display page alerts after a change in context, for example, when a user clicks a link or submits a form, launching a new page or an updated view
Write concise headings and copy - Provide further details in the appropriate section or page
Place page alerts underneath the page or subsection heading, as applicable
Ensure that page alerts include headings that clearly convey the purpose of the alert (for example, “Warning”)
Use an appropriate status – Please see the Guidelines for Alerts article
Don’t
Display alerts that are not related to the user’s current goal
Tips
Try to limit to one alert per page
Accessibility
The WCAG criteria outlined in this section were chosen because they represent some of the most common failures when designing and implementing these components. For a comprehensive list, please see Web Content Accessibility Guidelines (WCAG) 2.1 (w3.org).
1.4.3 Contrast (Minimum)
The intent of this success criterion is to provide enough contrast between text and its background so that it can be read by people with moderately low vision (who do not use contrast-enhancing assistive technology). Text that is larger and has wider character strokes is easier to read at lower contrast. The contrast requirement for larger text is therefore lower.
It is recommended to check colour contrast between the text and background using a contrast checking tool like the one provided by WebAIM WebAIM: Contrast Checker.
Understanding Success Criterion 1.4.3: Contrast (Minimum) | WAI | W3C
1.4.11 Non-text Contrast
The intent of this success criterion is to ensure that active user interface components (i.e., controls) and meaningful graphics are distinguishable by people with moderately low vision. Low contrast controls are more difficult to perceive, and may be completely missed by people with a visual impairment.
It is recommended to check that UI components have a contrast ratio of at least 3:1 against adjacent colours using a contrast checking tool like the one provided by WebAIM WebAIM: Contrast Checker.
Tip: There are contrast checking features built into some automated accessibility testing tools. However, these tools are not always capable of checking the contrast of different UI component states. For instance, if your page alert uses a dismiss button, it is recommended to manually test the contrast of its hover and focused states.
Understanding Success Criterion 1.4.11: Non-text Contrast | WAI | W3C
4.1.3 Status Messages
This criterion requires that, in content implemented using markup languages, status messages can be programmatically determined through role or properties such that they can be presented to the user by assistive technologies without receiving focus.
The intent of this success criterion is to make users aware of important changes in content that are not given focus, and to do so in a way that doesn't unnecessarily interrupt their work.
The intended beneficiaries are blind and low vision users of assistive technologies with screen reader capabilities.
Understanding Success Criterion 4.1.3: Status Messages | WAI | W3C
Key Component Features
Telerik provides four built-in notification types suitable for use as page alerts: error, warning, info and success. They also offer the option to define your own type by customizing the template and setting options for size, colour and position.
Blazor Notification Demos - Overview | Telerik UI for Blazor
Examples
Note: The following example is a visual illustration of how this component could be used in a MAACE application. Live examples of the Telerik UI component implemented in MAACE applications will be added when available.
Resources
Government of Canada Resources
Contextual alerts - Canada.ca design pattern - Canada.ca
Alert fatigue during COVID-19 | Canada.ca blog