uweb/searchurl/bml/content/rmi.js
2020-04-29 16:37:43 +08:00

79 lines
2.6 KiB
JavaScript

/**
* Remove all the IFRAMEs that are off-site or do not have a “src” attribute.
* These are typically used for ads and unwanted external content.
* navigation etc.
*
* IFRAMEs without a “src” attribute are also used for sandboxing untrusted
* content, e.g. on mailinator.com, but I have not yet found a way to
* distinguish between src-less IFRAMEs for ads and src-less IFRAMEs for
* “regular” content. Maybe try to guess based on the dimensions? Meh.
*
* @title rm IFRAMEs
*/
(function rmi() {
/* Create a new IFRAME to get a "clean" Window object, so we can use its
* console. Sometimes sites (e.g. Twitter) override console.log and even
* the entire console object. "delete console.log" or "delete console"
* does not always work, and messing with the prototype seemed more
* brittle than this. */
let console = (function () {
let iframe = document.getElementById('xxxJanConsole');
if (!iframe) {
iframe = document.createElementNS('http://www.w3.org/1999/xhtml', 'iframe');
iframe.id = 'xxxJanConsole';
iframe.style.display = 'none';
(document.body || document.documentElement).appendChild(iframe);
}
return iframe && iframe.contentWindow && iframe.contentWindow.console || {
log: function () {}
};
})();
/* Keep track of the HTMLDocument instances we have processed. */
let processed = new Set();
/**
* Is the given node empty-ish? I.e., does it lack child elements and
* non-whitespace text?
*/
function isEmpty(node) {
return !node || (!node.childElementCount && (typeof node.textContent !== 'string' || node.textContent.trim() === ''));
}
/* The main function. */
(function execute(document) {
if (!document || typeof document.querySelectorAll !== 'function' || processed.has(document)) {
return;
}
processed.add(document);
/* Process all IFRAMEs. */
Array.from(document.querySelectorAll('iframe:not(#xxxJanConsole)')).forEach(iframe => {
let shouldDelete = false;
try {
shouldDelete = iframe.contentDocument === null || iframe.src === '';
} catch (e) {
shouldDelete = true;
}
if (shouldDelete) {
console.log('rm IFRAMEs: found suspicious IFRAME to delete: ', iframe);
let parentNode = iframe.parentNode;
iframe.remove();
while (parentNode && isEmpty(parentNode)) {
console.log('rm IFRAMEs: found empty parent node to delete: ', parentNode);
let oldParentNode = parentNode;
parentNode = parentNode.parentNode;
oldParentNode.remove();
}
} else {
console.log('rm IFRAMEs: found non-suspicious IFRAME to recurse into: ', iframe);
execute(iframe.contentDocument);
}
});
})(document);
})();