javascript - 有没有办法绑定(bind)热键来触发链接？

Question

我正在尝试编写一个扩展程序，以允许 Facebook 用户将鼠标悬停在帖子顶部并按“L”键时点赞帖子。我之前在其他网站上取得了成功，当时将“喜欢”创建为按钮，但显然 Facebook 将“喜欢”创建为“链接”。

在此转换中，jQuery 的 .click() 命令无法触发实际的单击。有替代方案吗？

我使用的代码是:

$(window).keypress(function(e){
  if (e.keyCode == 108) {
    $('.x72:hover .UFILikeLink').click();
  }
});

Answer 1

使用悬停点击并不是一个好主意，因为 Facebook 有一个评论部分，当您输入评论时，按键操作将会被记录 - 但如果您使用一些罕见的按键，可能没问题。

另外，Facebook上的like按钮是通过a标签中的span实现的，而不是a标签本身，所以你需要的代码是:

$(window).keypress(function(e){
  if (e.keyCode == 108) {
    $('._4-u2:hover .UFILikeLink span').click();
  }
});

现在，如果您将来确实需要单击 a 标签，则以下是您需要的代码:

首先，生成虚假的浏览器点击:

;(function( $, undefined ) {

var rkeyEvent = /^key/,
  rmouseEvent = /^(?:mouse|contextmenu)|click/;

$.fn.simulate = function( type, options ) {
  return this.each(function() {
    new $.simulate( this, type, options );
  });
};

$.simulate = function( elem, type, options ) {
  var method = $.camelCase( "simulate-" + type );

  this.target = elem;
  this.options = options;

  if ( this[ method ] ) {
    this[ method ]();
  } else {
    this.simulateEvent( elem, type, options );
  }
};

$.extend( $.simulate, {

  keyCode: {
    BACKSPACE: 8,
    COMMA: 188,
    DELETE: 46,
    DOWN: 40,
    END: 35,
    ENTER: 13,
    ESCAPE: 27,
    HOME: 36,
    LEFT: 37,
    NUMPAD_ADD: 107,
    NUMPAD_DECIMAL: 110,
    NUMPAD_DIVIDE: 111,
    NUMPAD_ENTER: 108,
    NUMPAD_MULTIPLY: 106,
    NUMPAD_SUBTRACT: 109,
    PAGE_DOWN: 34,
    PAGE_UP: 33,
    PERIOD: 190,
    RIGHT: 39,
    SPACE: 32,
    TAB: 9,
    UP: 38
  },

  buttonCode: {
    LEFT: 0,
    MIDDLE: 1,
    RIGHT: 2
  }
});

$.extend( $.simulate.prototype, {

  simulateEvent: function( elem, type, options ) {
    var event = this.createEvent( type, options );
    this.dispatchEvent( elem, type, event, options );
  },

  createEvent: function( type, options ) {
    if ( rkeyEvent.test( type ) ) {
      return this.keyEvent( type, options );
    }

    if ( rmouseEvent.test( type ) ) {
      return this.mouseEvent( type, options );
    }
  },

  mouseEvent: function( type, options ) {
    var event, eventDoc, doc, body;
    options = $.extend({
      bubbles: true,
      cancelable: (type !== "mousemove"),
      view: window,
      detail: 0,
      screenX: 0,
      screenY: 0,
      clientX: 1,
      clientY: 1,
      ctrlKey: false,
      altKey: false,
      shiftKey: false,
      metaKey: false,
      button: 0,
      relatedTarget: undefined
    }, options );

    if ( document.createEvent ) {
      event = document.createEvent( "MouseEvents" );
      event.initMouseEvent( type, options.bubbles, options.cancelable,
        options.view, options.detail,
        options.screenX, options.screenY, options.clientX, options.clientY,
        options.ctrlKey, options.altKey, options.shiftKey, options.metaKey,
        options.button, options.relatedTarget || document.body.parentNode );

      // IE 9+ creates events with pageX and pageY set to 0.
      // Trying to modify the properties throws an error,
      // so we define getters to return the correct values.
      if ( event.pageX === 0 && event.pageY === 0 && Object.defineProperty ) {
        eventDoc = event.relatedTarget.ownerDocument || document;
        doc = eventDoc.documentElement;
        body = eventDoc.body;

        Object.defineProperty( event, "pageX", {
          get: function() {
            return options.clientX +
              ( doc && doc.scrollLeft || body && body.scrollLeft || 0 ) -
              ( doc && doc.clientLeft || body && body.clientLeft || 0 );
          }
        });
        Object.defineProperty( event, "pageY", {
          get: function() {
            return options.clientY +
              ( doc && doc.scrollTop || body && body.scrollTop || 0 ) -
              ( doc && doc.clientTop || body && body.clientTop || 0 );
          }
        });
      }
    } else if ( document.createEventObject ) {
      event = document.createEventObject();
      $.extend( event, options );
      // standards event.button uses constants defined here: http://msdn.microsoft.com/en-us/library/ie/ff974877(v=vs.85).aspx
      // old IE event.button uses constants defined here: http://msdn.microsoft.com/en-us/library/ie/ms533544(v=vs.85).aspx
      // so we actually need to map the standard back to oldIE
      event.button = {
        0: 1,
        1: 4,
        2: 2
      }[ event.button ] || ( event.button === -1 ? 0 : event.button );
    }

    return event;
  },

  keyEvent: function( type, options ) {
    var event;
    options = $.extend({
      bubbles: true,
      cancelable: true,
      view: window,
      ctrlKey: false,
      altKey: false,
      shiftKey: false,
      metaKey: false,
      keyCode: 0,
      charCode: undefined
    }, options );

    if ( document.createEvent ) {
      try {
        event = document.createEvent( "KeyEvents" );
        event.initKeyEvent( type, options.bubbles, options.cancelable, options.view,
          options.ctrlKey, options.altKey, options.shiftKey, options.metaKey,
          options.keyCode, options.charCode );
      // initKeyEvent throws an exception in WebKit
      // see: http://stackoverflow.com/questions/6406784/initkeyevent-keypress-only-works-in-firefox-need-a-cross-browser-solution
      // and also https://bugs.webkit.org/show_bug.cgi?id=13368
      // fall back to a generic event until we decide to implement initKeyboardEvent
      } catch( err ) {
        event = document.createEvent( "Events" );
        event.initEvent( type, options.bubbles, options.cancelable );
        $.extend( event, {
          view: options.view,
          ctrlKey: options.ctrlKey,
          altKey: options.altKey,
          shiftKey: options.shiftKey,
          metaKey: options.metaKey,
          keyCode: options.keyCode,
          charCode: options.charCode
        });
      }
    } else if ( document.createEventObject ) {
      event = document.createEventObject();
      $.extend( event, options );
    }

    if ( !!/msie [\w.]+/.exec( navigator.userAgent.toLowerCase() ) || (({}).toString.call( window.opera ) === "[object Opera]") ) {
      event.keyCode = (options.charCode > 0) ? options.charCode : options.keyCode;
      event.charCode = undefined;
    }

    return event;
  },

  dispatchEvent: function( elem, type, event ) {
    if ( elem[ type ] ) {
      elem[ type ]();
    } else if ( elem.dispatchEvent ) {
      elem.dispatchEvent( event );
    } else if ( elem.fireEvent ) {
      elem.fireEvent( "on" + type, event );
    }
  },

  simulateFocus: function() {
    var focusinEvent,
      triggered = false,
      element = $( this.target );

    function trigger() {
      triggered = true;
    }

    element.bind( "focus", trigger );
    element[ 0 ].focus();

    if ( !triggered ) {
      focusinEvent = $.Event( "focusin" );
      focusinEvent.preventDefault();
      element.trigger( focusinEvent );
      element.triggerHandler( "focus" );
    }
    element.unbind( "focus", trigger );
  },

  simulateBlur: function() {
    var focusoutEvent,
      triggered = false,
      element = $( this.target );

    function trigger() {
      triggered = true;
    }

    element.bind( "blur", trigger );
    element[ 0 ].blur();

    // blur events are async in IE
    setTimeout(function() {
      // IE won't let the blur occur if the window is inactive
      if ( element[ 0 ].ownerDocument.activeElement === element[ 0 ] ) {
        element[ 0 ].ownerDocument.body.focus();
      }

      // Firefox won't trigger events if the window is inactive
      // IE doesn't trigger events if we had to manually focus the body
      if ( !triggered ) {
        focusoutEvent = $.Event( "focusout" );
        focusoutEvent.preventDefault();
        element.trigger( focusoutEvent );
        element.triggerHandler( "blur" );
      }
      element.unbind( "blur", trigger );
    }, 1 );
  }
});



/** complex events **/

function findCenter( elem ) {
  var offset,
    document = $( elem.ownerDocument );
  elem = $( elem );
  offset = elem.offset();

  return {
    x: offset.left + elem.outerWidth() / 2 - document.scrollLeft(),
    y: offset.top + elem.outerHeight() / 2 - document.scrollTop()
  };
}

function findCorner( elem ) {
  var offset,
    document = $( elem.ownerDocument );
  elem = $( elem );
  offset = elem.offset();

  return {
    x: offset.left - document.scrollLeft(),
    y: offset.top - document.scrollTop()
  };
}

$.extend( $.simulate.prototype, {
  simulateDrag: function() {
    var i = 0,
      target = this.target,
      eventDoc = target.ownerDocument,
      options = this.options,
      center = options.handle === "corner" ? findCorner( target ) : findCenter( target ),
      x = Math.floor( center.x ),
      y = Math.floor( center.y ),
      coord = { clientX: x, clientY: y },
      dx = options.dx || ( options.x !== undefined ? options.x - x : 0 ),
      dy = options.dy || ( options.y !== undefined ? options.y - y : 0 ),
      moves = options.moves || 3;

    this.simulateEvent( target, "mousedown", coord );

    for ( ; i < moves ; i++ ) {
      x += dx / moves;
      y += dy / moves;

      coord = {
        clientX: Math.round( x ),
        clientY: Math.round( y )
      };

      this.simulateEvent( eventDoc, "mousemove", coord );
    }

    if ( $.contains( eventDoc, target ) ) {
      this.simulateEvent( target, "mouseup", coord );
      this.simulateEvent( target, "click", coord );
    } else {
      this.simulateEvent( eventDoc, "mouseup", coord );
    }
  }
});

})( jQuery );

现在您可以通过以下方式“模拟”点击:

$(window).keypress(function(e){
  if (e.keyCode == 108) {
    $('._4-u2:hover .UFILikeLink').simulate('click');
  }
});

干杯。