| /* |
| * Copyright (C) 2017 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' |
| * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
| * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS |
| * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
| * THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| function(element, attributeName) { |
| "use strict"; |
| |
| let lowercaseAttributeName = attributeName.toLowerCase(); |
| let tagName = element.tagName.toUpperCase(); |
| |
| // Special Case: "selected" / "checked" work analogously |
| // on options and checkboxes. |
| if (lowercaseAttributeName === "selected" || lowercaseAttributeName === "checked") { |
| switch (tagName) { |
| case "OPTION": |
| return element.selected ? "true" : null; |
| case "INPUT": |
| if (element.type === "checkbox" || element.type === "radio") |
| return element.checked ? "true" : null; |
| break; |
| } |
| } |
| |
| // Special Case: For images and links, require the existence of |
| // the attribute before accessing the property. |
| if ((tagName === "IMG" && lowercaseAttributeName === "src") || (tagName === "A" && lowercaseAttributeName === "href")) { |
| let value = element.getAttribute(lowercaseAttributeName); |
| return value ? element[lowercaseAttributeName] : value; |
| } |
| |
| // Prefer the element's property over the attribute if the |
| // property value is not null and not an object. For boolean |
| // properties return null if false. |
| try { |
| const propertyNameAliases = {"class": "className", "readonly": "readOnly"}; |
| let propertyName = propertyNameAliases[attributeName] || attributeName; |
| let value = element[propertyName]; |
| if (value != null && typeof value !== "object") { |
| if (typeof value === "boolean") |
| return value ? "true" : null; |
| return value.toString(); |
| } |
| } catch (e) { } |
| |
| return element.getAttribute(attributeName); |
| } |