Run custom JavaScript directly inside your automated tests
DoesQA includes thousands of built-in configurations and nodes, but sometimes you need something bespoke.
The Run Browser Script step allows you to inject and execute your own JavaScript directly inside the browser during a test. This gives you full flexibility to handle domain-specific logic, advanced assertions, or edge cases that go beyond standard test steps.
If you can write it in JavaScript, you can run it inside your flow.
Extend your automation without leaving DoesQA
With Run Browser Script, you can:
Mutate the DOM before or after actions
Perform custom validations
Read complex page state
Combine multiple element values
Execute calculations
Trigger custom events
Interact with client-side frameworks
This makes it ideal for advanced scenarios where your application logic is highly dynamic or tailored to your business.
Create powerful custom assertions
Some checks are too specific for generic validation steps. For example:
Verifying a bespoke sorting algorithm
Comparing multiple table values against complex rules
Checking dynamic pricing logic
Validating calculated totals
Ensuring feature flags alter behaviour correctly
With custom JavaScript, you can implement exactly the logic your product requires.
You can also return values from the script to use later in your test, making it possible to chain advanced logic across steps.
Access your dynamic values at runtime
The custom script has access to all available values at the point of execution, including:
Environment variables
Stored values
Dynamic values
Data generated earlier in the flow
This allows you to combine application state with test state for precise and context-aware automation.
For example:
Generate custom test data on the fly
Compute derived values
Validate data against environment-specific configuration
Mutate the DOM when needed
There are legitimate cases where adjusting the DOM during testing can be useful. For example:
Temporarily removing blocking overlays
Simulating edge-case UI states
Injecting mock data into client-side applications
Forcing a component into a testable state
This level of control ensures your automation can adapt to even complex front-end architectures.
Build reusable advanced logic
When paired with Node Groups, custom browser scripts can become reusable building blocks.
You can:
Group your custom script into a reusable node group
Edit it centrally
Use it across multiple flows
Maintain complex logic in one place
This allows teams to standardise advanced behaviours and reduce duplication across large test packs.
Full flexibility without losing structure
Run Browser Script is not a replacement for structured automation. It is a precision tool.
Use it when:
Built-in nodes are not enough
You need domain-specific logic
You want deeper control over the browser
You need highly customised validation
It gives experienced testers and developers the power of JavaScript, directly inside a structured visual test builder.
This means you can maintain clarity and collaboration, while still handling even the most complex automation requirements.