How to read hidden attributes from a page loaded in SWT Browser - eclipse-plugin

Question

I am working on an Eclipse plugin which loads a URL in the SWT browser. This page rendered in the browser has hidden html attributes. The requirement is to read the values of the hidden attributes.
Browser browser = new Browser(shell, SWT.NONE);
browser.setUrl("www.<my_url>.com");
I tried to execute a query on the DOM using the statusTextListener
browser.addStatusTextListener(new StatusTextListener() {
public void changed(StatusTextEvent event) {
browser.setData("query", event.text);
}
});
browser.addProgressListener(new ProgressListener() {
public void completed(ProgressEvent event) {
boolean result = browser
.execute("window.status=document.getElementById('main').childNodes[0].nodeValue;");
if (!result) {
/* Script may fail or may not be supported on certain platforms. */
System.out.println("Script was not executed.");
return;
}
String value = (String) browser.getData("query");
System.out.println("Node value: " + value);
}
});
However this does not seem to work. It works well if I try to load HTML text in the browser instead of the URL.
Any idea how to read DOM elements from the SWT browser after the page load is complete?

Answer 1

Use Browser::evaluate to execute Javascript in the context of the document and return the result to the caller.
To obtain the value of the first child of the main element in your example, start like this:
String script = "<Javascript to return an array of hidden attribute names>";
Object result = browser.evaluate(script);
The supported result types, however, are limited to string, number, and boolean - and arrays of these types. Javascript that evaluates to null or undefined will return null.
Hence, you will need to adjust your Javascript that queries the DOM to return a supported type.