diff options
Diffstat (limited to 'content_scripts/link_hints.coffee')
| -rw-r--r-- | content_scripts/link_hints.coffee | 57 |
1 files changed, 46 insertions, 11 deletions
diff --git a/content_scripts/link_hints.coffee b/content_scripts/link_hints.coffee index 3088812b..1795f0f7 100644 --- a/content_scripts/link_hints.coffee +++ b/content_scripts/link_hints.coffee @@ -189,7 +189,9 @@ LocalHints = tagName = element.tagName.toLowerCase() isClickable = false onlyHasTabIndex = false + possibleFalsePositive = false visibleElements = [] + reason = null # Insert area elements that provide click functionality to an img. if tagName == "img" @@ -228,7 +230,6 @@ LocalHints = # Check for attributes that make an element clickable regardless of its tagName. if (element.hasAttribute("onclick") or element.getAttribute("role")?.toLowerCase() in ["button", "link"] or - element.getAttribute("class")?.toLowerCase().indexOf("button") >= 0 or element.getAttribute("contentEditable")?.toLowerCase() in ["", "contentEditable", "true"]) isClickable = true @@ -254,8 +255,21 @@ LocalHints = when "label" isClickable ||= element.control? and (@getVisibleClickable element.control).length == 0 when "body" - isClickable ||= element == document.body and not document.hasFocus() and - window.innerWidth > 3 and window.innerHeight > 3 + isClickable ||= + if element == document.body and not document.hasFocus() and + window.innerWidth > 3 and window.innerHeight > 3 and + document.body?.tagName.toLowerCase() != "frameset" + reason = "Frame." + when "div", "ol", "ul" + isClickable ||= + if element.clientHeight < element.scrollHeight and Scroller.isScrollableElement element + reason = "Scroll." + + # An element with a class name containing the text "button" might be clickable. However, real clickables + # are often wrapped in elements with such class names. So, when we find clickables based only on their + # class name, we mark them as unreliable. + if not isClickable and 0 <= element.getAttribute("class")?.toLowerCase().indexOf "button" + possibleFalsePositive = isClickable = true # Elements with tabindex are sometimes useful, but usually not. We can treat them as second class # citizens when it improves UX, so take special note of them. @@ -267,7 +281,8 @@ LocalHints = if isClickable clientRect = DomUtils.getVisibleClientRect element, true if clientRect != null - visibleElements.push {element: element, rect: clientRect, secondClassCitizen: onlyHasTabIndex} + visibleElements.push {element: element, rect: clientRect, secondClassCitizen: onlyHasTabIndex, + possibleFalsePositive, reason} visibleElements @@ -291,6 +306,27 @@ LocalHints = visibleElement = @getVisibleClickable element visibleElements.push visibleElement... + # Traverse the DOM from descendants to ancestors, so later elements show above earlier elements. + visibleElements = visibleElements.reverse() + + # Filter out suspected false positives. A false positive is taken to be an element marked as a possible + # false positive for which a close descendant is already clickable. False positives tend to be close + # together in the DOM, so - to keep the cost down - we only search nearby elements. NOTE(smblott): The + # visible elements have already been reversed, so we're visiting descendants before their ancestors. + descendantsToCheck = [1..3] # This determines how many descendants we're willing to consider. + visibleElements = + for element, position in visibleElements + continue if element.possibleFalsePositive and do -> + index = Math.max 0, position - 6 # This determines how far back we're willing to look. + while index < position + candidateDescendant = visibleElements[index].element + for _ in descendantsToCheck + candidateDescendant = candidateDescendant?.parentElement + return true if candidateDescendant == element.element + index += 1 + false # This is not a false positive. + element + # TODO(mrmr1993): Consider z-index. z-index affects behviour as follows: # * The document has a local stacking context. # * An element with z-index specified @@ -305,15 +341,13 @@ LocalHints = # # Remove rects from elements where another clickable element lies above it. localHints = nonOverlappingElements = [] - # Traverse the DOM from first to last, since later elements show above earlier elements. - visibleElements = visibleElements.reverse() while visibleElement = visibleElements.pop() rects = [visibleElement.rect] for {rect: negativeRect} in visibleElements # Subtract negativeRect from every rect in rects, and concatenate the arrays of rects that result. rects = [].concat (rects.map (rect) -> Rect.subtract rect, negativeRect)... if rects.length > 0 - nonOverlappingElements.push {element: visibleElement.element, rect: rects[0]} + nonOverlappingElements.push extend visibleElement, rect: rects[0] else # Every part of the element is covered by some other element, so just insert the whole element's # rect. Except for elements with tabIndex set (second class citizens); these are often more trouble @@ -325,7 +359,7 @@ LocalHints = hint.hasHref = hint.element.href? for hint in localHints if Settings.get "filterLinkHints" @withLabelMap (labelMap) => - extend hint, @generateLinkText labelMap, hint.element for hint in localHints + extend hint, @generateLinkText labelMap, hint for hint in localHints localHints # Generate a map of input element => label text, call a callback with it. @@ -342,7 +376,8 @@ LocalHints = labelMap[forElement] = labelText callback labelMap - generateLinkText: (labelMap, element) -> + generateLinkText: (labelMap, hint) -> + element = hint.element linkText = "" showLinkText = false # toLowerCase is necessary as html documents return "IMG" and xhtml documents return "img" @@ -362,8 +397,8 @@ LocalHints = element.firstElementChild.nodeName.toLowerCase() == "img" linkText = element.firstElementChild.alt || element.firstElementChild.title showLinkText = true if linkText - else if element == document.body - linkText = "Frame." + else if hint.reason? + linkText = hint.reason showLinkText = true else linkText = (element.textContent.trim() || element.innerHTML.trim())[...512] |