browser_wait_for_function
Wait for a custom JavaScript condition to become true. Useful for waiting on application-specific state like 'window.appReady' or complex DOM conditions that can't be expressed with a selector.
When to use browser_wait_for_function
Use browser_wait_for_function when you need to synchronize your script with the real state of a loading page. It is part of Owl Browser's Wait Utilities toolset and runs inside a self-hosted, source-level stealth engine, so every call uses the same configured fingerprint controls as the rest of your automation. Detection still depends on the site, network, behavior, and profile consistency.
Usage Example
Parameters
Required
context_idstringrequiredThe unique identifier of the browser context (e.g., 'ctx_000001')
js_functionstringrequiredJavaScript code that returns truthy value when condition is met. Executed repeatedly until true or timeout. Examples: 'return document.querySelector(".loaded") !== null', 'return window.dataReady === true'
Optional
pollingintegerInterval between function evaluations in milliseconds. Lower = more responsive but more CPU. Default: 100ms
timeoutintegerMaximum time to wait for function to return true. Default: 30000 (30 seconds)
Response
Returns a JSON object with the operation result.
{
"success": true,
"result": <value>
}Frequently Asked Questions
What does browser_wait_for_function do?
Wait for a custom JavaScript condition to become true. Useful for waiting on application-specific state like 'window.appReady' or complex DOM conditions that can't be expressed with a selector. It belongs to Owl Browser's Wait Utilities category and is available through the REST API, the Python SDK (browser.wait_for_function()), the Node.js SDK, and the MCP server.
What parameters does browser_wait_for_function accept?
browser_wait_for_function accepts 2 required parameters (context_id, js_function) and 2 optional parameters. All parameters are sent as JSON in a POST request to /api/execute/browser_wait_for_function.
Is browser_wait_for_function detectable by anti-bot systems like Cloudflare or DataDome?
No. browser_wait_for_function executes inside Owl Browser's Chromium engine, which applies fingerprint spoofing at the C++ source level rather than through JavaScript patches. Every tool call shares the same consistent, human-like fingerprint, so anti-bot systems such as Cloudflare, DataDome, and Akamai see an ordinary browser.
Related Tools
browser_wait_for_selectorWait for an element matching the selector to appear and become visible on the page. Essential for handling dynamic content that loads after navigation. Times out with error if element doesn't appear.
browser_waitPause execution for a fixed number of milliseconds. Use sparingly - prefer browser_wait_for_selector or browser_wait_for_network_idle for more reliable synchronization.
browser_wait_for_network_idleWait until there are no pending network requests for a specified duration. The most reliable way to wait for a page to fully load, including AJAX requests, images, and dynamic content.
browser_wait_for_urlWait for the page URL to match a specific pattern. Useful after clicking links or submitting forms to ensure navigation completed. Supports substring matching or glob patterns with wildcards.
browser_wait_for_downloadBlock until a specific download completes or times out. Returns true on completion; call browser_get_downloads afterwards for the file path and final status. Use after triggering a download to ensure it finishes before proceeding.
browser_wait_for_dialogWait for a JavaScript dialog to appear. Blocks until a dialog shows up or timeout expires. Useful when you know an action will trigger a dialog and need to handle it specifically.