Yang Xiaoxiao / 2020website

/*! responsive-nav.js 1.0.39
 * https://github.com/viljamis/responsive-nav.js
 * http://responsive-nav.com
 *
 * Copyright (c) 2015 @viljamis
 * Available under the MIT license
 */

/* global Event */
(function (document, window, index) {
  // Index is used to keep multiple navs on the same page namespaced

  "use strict";

  var responsiveNav = function (el, options) {

    var computed = !!window.getComputedStyle;
    
    /**
     * getComputedStyle polyfill for old browsers
     */
    if (!computed) {
      window.getComputedStyle = function(el) {
        this.el = el;
        this.getPropertyValue = function(prop) {
          var re = /(\-([a-z]){1})/g;
          if (prop === "float") {
            prop = "styleFloat";
          }
          if (re.test(prop)) {
            prop = prop.replace(re, function () {
              return arguments[2].toUpperCase();
            });
          }
          return el.currentStyle[prop] ? el.currentStyle[prop] : null;
        };
        return this;
      };
    }
    /* exported addEvent, removeEvent, getChildren, setAttributes, addClass, removeClass, forEach */
    
    /**
     * Add Event
     * fn arg can be an object or a function, thanks to handleEvent
     * read more at: http://www.thecssninja.com/javascript/handleevent
     *
     * @param  {element}  element
     * @param  {event}    event
     * @param  {Function} fn
     * @param  {boolean}  bubbling
     */
    var addEvent = function (el, evt, fn, bubble) {
        if ("addEventListener" in el) {
          // BBOS6 doesn't support handleEvent, catch and polyfill
          try {
            el.addEventListener(evt, fn, bubble);
          } catch (e) {
            if (typeof fn === "object" && fn.handleEvent) {
              el.addEventListener(evt, function (e) {
                // Bind fn as this and set first arg as event object
                fn.handleEvent.call(fn, e);
              }, bubble);
            } else {
              throw e;
            }
          }
        } else if ("attachEvent" in el) {
          // check if the callback is an object and contains handleEvent
          if (typeof fn === "object" && fn.handleEvent) {
            el.attachEvent("on" + evt, function () {
              // Bind fn as this
              fn.handleEvent.call(fn);
            });
          } else {
            el.attachEvent("on" + evt, fn);
          }
        }
      },
    
      /**
       * Remove Event
       *
       * @param  {element}  element
       * @param  {event}    event
       * @param  {Function} fn
       * @param  {boolean}  bubbling
       */
      removeEvent = function (el, evt, fn, bubble) {
        if ("removeEventListener" in el) {
          try {
            el.removeEventListener(evt, fn, bubble);
          } catch (e) {
            if (typeof fn === "object" && fn.handleEvent) {
              el.removeEventListener(evt, function (e) {
                fn.handleEvent.call(fn, e);
              }, bubble);
            } else {
              throw e;
            }
          }
        } else if ("detachEvent" in el) {
          if (typeof fn === "object" && fn.handleEvent) {
            el.detachEvent("on" + evt, function () {
              fn.handleEvent.call(fn);
            });
          } else {
            el.detachEvent("on" + evt, fn);
          }
        }
      },
    
      /**
       * Get the children of any element
       *
       * @param  {element}
       * @return {array} Returns matching elements in an array
       */
      getChildren = function (e) {
        if (e.children.length < 1) {
          throw new Error("The Nav container has no containing elements");
        }
        // Store all children in array
        var children = [];
        // Loop through children and store in array if child != TextNode
        for (var i = 0; i < e.children.length; i++) {
          if (e.children[i].nodeType === 1) {
            children.push(e.children[i]);
          }
        }
        return children;
      },
    
      /**
       * Sets multiple attributes at once
       *
       * @param {element} element
       * @param {attrs}   attrs
       */
      setAttributes = function (el, attrs) {
        for (var key in attrs) {
          el.setAttribute(key, attrs[key]);
        }
      },
    
      /**
       * Adds a class to any element
       *
       * @param {element} element
       * @param {string}  class
       */
      addClass = function (el, cls) {
        if (el.className.indexOf(cls) !== 0) {
          el.className += " " + cls;
          el.className = el.className.replace(/(^\s*)|(\s*$)/g,"");
        }
      },
    
      /**
       * Remove a class from any element
       *
       * @param  {element} element
       * @param  {string}  class
       */
      removeClass = function (el, cls) {
        var reg = new RegExp("(\\s|^)" + cls + "(\\s|$)");
        el.className = el.className.replace(reg, " ").replace(/(^\s*)|(\s*$)/g,"");
      },
    
      /**
       * forEach method that passes back the stuff we need
       *
       * @param  {array}    array
       * @param  {Function} callback
       * @param  {scope}    scope
       */
      forEach = function (array, callback, scope) {
        for (var i = 0; i < array.length; i++) {
          callback.call(scope, i, array[i]);
        }
      };

    var nav,
      opts,
      navToggle,
      styleElement = document.createElement("style"),
      htmlEl = document.documentElement,
      hasAnimFinished,
      isMobile,
      navOpen;

    var ResponsiveNav = function (el, options) {
        var i;

        /**
         * Default options
         * @type {Object}
         */
        this.options = {
          animate: true,                    // Boolean: Use CSS3 transitions, true or false
          transition: 284,                  // Integer: Speed of the transition, in milliseconds
          label: "Menu",                    // String: Label for the navigation toggle
          insert: "before",                 // String: Insert the toggle before or after the navigation
          customToggle: "",                 // Selector: Specify the ID of a custom toggle
          closeOnNavClick: false,           // Boolean: Close the navigation when one of the links are clicked
          openPos: "relative",              // String: Position of the opened nav, relative or static
          navClass: "nav-collapse",         // String: Default CSS class. If changed, you need to edit the CSS too!
          navActiveClass: "js-nav-active",  // String: Class that is added to <html> element when nav is active
          jsClass: "js",                    // String: 'JS enabled' class which is added to <html> element
          init: function(){},               // Function: Init callback
          open: function(){},               // Function: Open callback
          close: function(){}               // Function: Close callback
        };

        // User defined options
        for (i in options) {
          this.options[i] = options[i];
        }

        // Adds "js" class for <html>
        addClass(htmlEl, this.options.jsClass);

        // Wrapper
        this.wrapperEl = el.replace("#", "");

        // Try selecting ID first
        if (document.getElementById(this.wrapperEl)) {
          this.wrapper = document.getElementById(this.wrapperEl);

        // If element with an ID doesn't exist, use querySelector
        } else if (document.querySelector(this.wrapperEl)) {
          this.wrapper = document.querySelector(this.wrapperEl);

        // If element doesn't exists, stop here.
        } else {
          throw new Error("The nav element you are trying to select doesn't exist");
        }

        // Inner wrapper
        this.wrapper.inner = getChildren(this.wrapper);

        // For minification
        opts = this.options;
        nav = this.wrapper;

        // Init
        this._init(this);
      };

    ResponsiveNav.prototype = {

      /**
       * Unattaches events and removes any classes that were added
       */
      destroy: function () {
        this._removeStyles();
        removeClass(nav, "closed");
        removeClass(nav, "opened");
        removeClass(nav, opts.navClass);
        removeClass(nav, opts.navClass + "-" + this.index);
        removeClass(htmlEl, opts.navActiveClass);
        nav.removeAttribute("style");
        nav.removeAttribute("aria-hidden");

        removeEvent(window, "resize", this, false);
        removeEvent(window, "focus", this, false);
        removeEvent(document.body, "touchmove", this, false);
        removeEvent(navToggle, "touchstart", this, false);
        removeEvent(navToggle, "touchend", this, false);
        removeEvent(navToggle, "mouseup", this, false);
        removeEvent(navToggle, "keyup", this, false);
        removeEvent(navToggle, "click", this, false);

        if (!opts.customToggle) {
          navToggle.parentNode.removeChild(navToggle);
        } else {
          navToggle.removeAttribute("aria-hidden");
        }
      },

      /**
       * Toggles the navigation open/close
       */
      toggle: function () {
        if (hasAnimFinished === true) {
          if (!navOpen) {
            this.open();
          } else {
            this.close();
          }
        }
      },

      /**
       * Opens the navigation
       */
      open: function () {
        if (!navOpen) {
          removeClass(nav, "closed");
          addClass(nav, "opened");
          addClass(htmlEl, opts.navActiveClass);
          addClass(navToggle, "active");
          nav.style.position = opts.openPos;
          setAttributes(nav, {"aria-hidden": "false"});
          navOpen = true;
          opts.open();
        }
      },

      /**
       * Closes the navigation
       */
      close: function () {
        if (navOpen) {
          addClass(nav, "closed");
          removeClass(nav, "opened");
          removeClass(htmlEl, opts.navActiveClass);
          removeClass(navToggle, "active");
          setAttributes(nav, {"aria-hidden": "true"});

          // If animations are enabled, wait until they finish
          if (opts.animate) {
            hasAnimFinished = false;
            setTimeout(function () {
              nav.style.position = "absolute";
              hasAnimFinished = true;
            }, opts.transition + 10);

          // Animations aren't enabled, we can do these immediately
          } else {
            nav.style.position = "absolute";
          }

          navOpen = false;
          opts.close();
        }
      },

      /**
       * Resize is called on window resize and orientation change.
       * It initializes the CSS styles and height calculations.
       */
      resize: function () {

        // Resize watches navigation toggle's display state
        if (window.getComputedStyle(navToggle, null).getPropertyValue("display") !== "none") {

          isMobile = true;
          setAttributes(navToggle, {"aria-hidden": "false"});

          // If the navigation is hidden
          if (nav.className.match(/(^|\s)closed(\s|$)/)) {
            setAttributes(nav, {"aria-hidden": "true"});
            nav.style.position = "absolute";
          }

          this._createStyles();
          this._calcHeight();
        } else {

          isMobile = false;
          setAttributes(navToggle, {"aria-hidden": "true"});
          setAttributes(nav, {"aria-hidden": "false"});
          nav.style.position = opts.openPos;
          this._removeStyles();
        }
      },

      /**
       * Takes care of all even handling
       *
       * @param  {event} event
       * @return {type} returns the type of event that should be used
       */
      handleEvent: function (e) {
        var evt = e || window.event;

        switch (evt.type) {
        case "touchstart":
          this._onTouchStart(evt);
          break;
        case "touchmove":
          this._onTouchMove(evt);
          break;
        case "touchend":
        case "mouseup":
          this._onTouchEnd(evt);
          break;
        case "click":
          this._preventDefault(evt);
          break;
        case "keyup":
          this._onKeyUp(evt);
          break;
        case "focus":
        case "resize":
          this.resize(evt);
          break;
        }
      },

      /**
       * Initializes the widget
       */
      _init: function () {
        this.index = index++;

        addClass(nav, opts.navClass);
        addClass(nav, opts.navClass + "-" + this.index);
        addClass(nav, "closed");
        hasAnimFinished = true;
        navOpen = false;

        this._closeOnNavClick();
        this._createToggle();
        this._transitions();
        this.resize();

        /**
         * On IE8 the resize event triggers too early for some reason
         * so it's called here again on init to make sure all the
         * calculated styles are correct.
         */
        var self = this;
        setTimeout(function () {
          self.resize();
        }, 20);

        addEvent(window, "resize", this, false);
        addEvent(window, "focus", this, false);
        addEvent(document.body, "touchmove", this, false);
        addEvent(navToggle, "touchstart", this, false);
        addEvent(navToggle, "touchend", this, false);
        addEvent(navToggle, "mouseup", this, false);
        addEvent(navToggle, "keyup", this, false);
        addEvent(navToggle, "click", this, false);

        /**
         * Init callback here
         */
        opts.init();
      },

      /**
       * Creates Styles to the <head>
       */
      _createStyles: function () {
        if (!styleElement.parentNode) {
          styleElement.type = "text/css";
          document.getElementsByTagName("head")[0].appendChild(styleElement);
        }
      },

      /**
       * Removes styles from the <head>
       */
      _removeStyles: function () {
        if (styleElement.parentNode) {
          styleElement.parentNode.removeChild(styleElement);
        }
      },

      /**
       * Creates Navigation Toggle
       */
      _createToggle: function () {

        // If there's no toggle, let's create one
        if (!opts.customToggle) {
          var toggle = document.createElement("a");
          toggle.innerHTML = opts.label;
          setAttributes(toggle, {
            "href": "#",
            "class": "nav-toggle"
          });

          // Determine where to insert the toggle
          if (opts.insert === "after") {
            nav.parentNode.insertBefore(toggle, nav.nextSibling);
          } else {
            nav.parentNode.insertBefore(toggle, nav);
          }

          navToggle = toggle;

        // There is a toggle already, let's use that one
        } else {
          var toggleEl = opts.customToggle.replace("#", "");

          if (document.getElementById(toggleEl)) {
            navToggle = document.getElementById(toggleEl);
          } else if (document.querySelector(toggleEl)) {
            navToggle = document.querySelector(toggleEl);
          } else {
            throw new Error("The custom nav toggle you are trying to select doesn't exist");
          }
        }
      },

      /**
       * Closes the navigation when a link inside is clicked.
       */
      _closeOnNavClick: function () {
        if (opts.closeOnNavClick) {
          var links = nav.getElementsByTagName("a"),
            self = this;
          forEach(links, function (i, el) {
            addEvent(links[i], "click", function () {
              if (isMobile) {
                self.toggle();
              }
            }, false);
          });
        }
      },

      /**
       * Prevents the default functionality.
       *
       * @param  {event} event
       */
      _preventDefault: function(e) {
        if (e.preventDefault) {
          if (e.stopImmediatePropagation) {
            e.stopImmediatePropagation();
          }
          e.preventDefault();
          e.stopPropagation();
          return false;

        // This is strictly for old IE
        } else {
          e.returnValue = false;
        }
      },

      /**
       * On touch start we get the location of the touch.
       *
       * @param  {event} event
       */
      _onTouchStart: function (e) {
        if (!Event.prototype.stopImmediatePropagation) {
          this._preventDefault(e);
        }
        this.startX = e.touches[0].clientX;
        this.startY = e.touches[0].clientY;
        this.touchHasMoved = false;

        /**
         * Remove mouseup event completely here to avoid
         * double triggering the event.
         */
        removeEvent(navToggle, "mouseup", this, false);
      },

      /**
       * Check if the user is scrolling instead of tapping.
       *
       * @param  {event} event
       */
      _onTouchMove: function (e) {
        if (Math.abs(e.touches[0].clientX - this.startX) > 10 ||
        Math.abs(e.touches[0].clientY - this.startY) > 10) {
          this.touchHasMoved = true;
        }
      },

      /**
       * On touch end toggle the navigation.
       *
       * @param  {event} event
       */
      _onTouchEnd: function (e) {
        this._preventDefault(e);
        if (!isMobile) {
          return;
        }

        // If the user isn't scrolling
        if (!this.touchHasMoved) {

          // If the event type is touch
          if (e.type === "touchend") {
            this.toggle();
            return;

          // Event type was click, not touch
          } else {
            var evt = e || window.event;

            // If it isn't a right click, do toggling
            if (!(evt.which === 3 || evt.button === 2)) {
              this.toggle();
            }
          }
        }
      },

      /**
       * For keyboard accessibility, toggle the navigation on Enter
       * keypress too.
       *
       * @param  {event} event
       */
      _onKeyUp: function (e) {
        var evt = e || window.event;
        if (evt.keyCode === 13) {
          this.toggle();
        }
      },

      /**
       * Adds the needed CSS transitions if animations are enabled
       */
      _transitions: function () {
        if (opts.animate) {
          var objStyle = nav.style,
            transition = "max-height " + opts.transition + "ms";

          objStyle.WebkitTransition =
          objStyle.MozTransition =
          objStyle.OTransition =
          objStyle.transition = transition;
        }
      },

      /**
       * Calculates the height of the navigation and then creates
       * styles which are later added to the page <head>
       */
      _calcHeight: function () {
        var savedHeight = 0;
        for (var i = 0; i < nav.inner.length; i++) {
          savedHeight += nav.inner[i].offsetHeight;
        }

        var innerStyles = "." + opts.jsClass + " ." + opts.navClass + "-" + this.index + ".opened{max-height:" + savedHeight + "px !important} ." + opts.jsClass + " ." + opts.navClass + "-" + this.index + ".opened.dropdown-active {max-height:9999px !important}";

        if (styleElement.styleSheet) {
          styleElement.styleSheet.cssText = innerStyles;
        } else {
          styleElement.innerHTML = innerStyles;
        }

        innerStyles = "";
      }

    };

    /**
     * Return new Responsive Nav
     */
    return new ResponsiveNav(el, options);

  };

  if (typeof module !== "undefined" && module.exports) {
    module.exports = responsiveNav;
  } else {
    window.responsiveNav = responsiveNav;
  }

}(document, window, 0));