LinkChecker is a simple, lightweight JavaScript framework that assists in checking for broken links.
Core Types
LinkChecker.Link
The
Link type is used to check an individual url. Construct a Link type by passing in a DOM element that is either an anchor or an image (beware that this is not enforced in code)://assume HTML:
//<a href="/some/local/link" id="someElement">Link Text</a>
var someLink = new LinkChecker.Link(document.getElementById("someElement"));
Call the
isLocal() method to check whether checking the link will violate the same-origin policy. This is a safety measure that is a necessity unless you have disabled the same-origin policy in your browser.if(someLink.isLocal()) {
//do something
}
Assuming our link was local, check whether its broken. In the callback,
this is bound to the link object and the brokenproperty stores the result of the check://supply callback for when request has completed
//within the callback, 'this' is bound to the Link object
link.check(function() {
console.log("Checked URI '%s' on element with ID '%s'. Is broken: %s", " this.uri, this.elem.id, this.broken);
});
LinkChecker.LinkProcessor
The
LinkProcessor type is used to batch process links. URLs will only be checked once if the URL exists in more than one location in a document
To construct a
LinkProcessor supply an array of relevant DOM elements://we will check every link in the document
var processor = new LinkChecker.LinkProcessor(document.getElementsByTagName("a"));
LinkProcessor uses a pub/sub system to give plenty of flexibilty in how you wish to use it. The events exposed byLinkProcessor can be found in LinkChecker.events object. Use the on(string, function) method to subscribe to an event.
The started event is fired immediately before processing begins:
processor.on(LinkChecker.events.started, function(numberOfLinks) {
//callback is supplied with number of links to be processed
//filtered by those which do not violate same-origin policy (a subset of the links passed into constructor)
console.log("beginning processing of %i links", numberOfLinks);
});
The checked event is called after each link has been checked:
processor.on(LinkChecker.events.checked, function(link) {
//callback is supplied with a primed link object
console.log("checked uri: '%s', is broken: %s", " link.uri, link.broken); //checked uri: '/some/local/link', is broken: false
});
The completed event is supplied with an array of all processed Links:
processor.on(LinkChecker.events.completed, function(processed) {
var count = 0;
//tally up broken links
for(var i = 0; i < processed.length; i++) {
if(processed[i].broken) {
count++;
}
}
//output a summary
console.log("completed processing, found %i broken links", count);
});
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