$("p").on("click",function(){  alert("The paragraph was clicked.");});$("#box1").off("click");

{  type: type,  origType: origType,  data: data,  handler: handler,  guid: guid,  selector: selector,  needsContext: needsContext,  namespace: namespace}

"div#box":{ //元素  "Jquery623873":{ //元素的緩存    "events":{       "click":[       {  //元素click事件的事件數(shù)據(jù)             type: type,             origType: origType,             data: data,             handler: handler,             guid: guid,             selector: selector,             needsContext: needsContext,             namespace: namespace               }      ],      "mousemove":[       {             type: type,             origType: origType,             data: data,             handler: handler,             guid: guid,             selector: selector,             needsContext: needsContext,             namespace: namespace               }      ]    }  }}

jQuery.fn.extend( {  on: function( types, selector, data, fn ) {    return on( this, types, selector, data, fn );  },  one: function( types, selector, data, fn ) {    return on( this, types, selector, data, fn, 1 );  },  off: function( types, selector, fn ) {    //此處省略處理參數(shù)的代碼    return this.each( function() {      jQuery.event.remove( this, types, fn, selector );    } );  }} );

function on( elem, types, selector, data, fn, one ) {  var origFn, type;  //此處省略處理參數(shù)的代碼  //是否是通過one綁定，是的話使用一個函數(shù)代理當(dāng)前事件回調(diào)函數(shù)，代理函數(shù)只執(zhí)行一次  //這里使用到了代理模式  if ( one === 1 ) {       origFn = fn;    fn = function( event ) {      // Can use an empty set, since event contains the info      jQuery().off( event );      return origFn.apply( this, arguments );    };    // Use same guid so caller can remove using origFn    fn.guid = origFn.guid || ( origFn.guid = jQuery.guid++ );  }  /************************************************  *** jquery將所有選擇到的元素到放到一個數(shù)組里，然后  *** 對每個元素到使用event對象的add方法綁定事件  *************************************************/  return elem.each( function() {    jQuery.event.add( this, types, fn, data, selector );  } );}

jQuery.event = {  add: function( elem, types, handler, data, selector ) {    var handleObjIn, eventHandle, tmp,      events, t, handleObj,      special, handlers, type, namespaces, origType,      elemData = dataPriv.get( elem );  //這句將檢查elem是否被緩存，如果沒有將會創(chuàng)建一個緩存添加到elem元素上。形式諸如：elem["jQuery310057655476080253721"] = {}    // Don't attach events to noData or text/comment nodes (but allow plain objects)    if ( !elemData ) {      return;    }    //用戶可以傳入一個自定義數(shù)據(jù)對象來代替事件回調(diào)函數(shù)，將事件回調(diào)函數(shù)放在這個數(shù)據(jù)對象的handler屬性里    if ( handler.handler ) {      handleObjIn = handler;      handler = handleObjIn.handler;      selector = handleObjIn.selector;    }    //每個事件回調(diào)函數(shù)都會生成一個唯一的id，以后find/remove的時候會用到    if ( !handler.guid ) {      handler.guid = jQuery.guid++;    }    // 如果元素第一次綁定事件，則初始化元素的事件數(shù)據(jù)結(jié)構(gòu)和主回調(diào)函數(shù)（main）    //說明：每個元素有一個主回調(diào)函數(shù)，作為綁定多個事件到該元素時的回調(diào)的入口    if ( !( events = elemData.events ) ) {      events = elemData.events = {};    }    //這里就是初始化主回調(diào)函數(shù)的代碼    if ( !( eventHandle = elemData.handle ) ) {      eventHandle = elemData.handle = function( e ) {        // Discard the second event of a jQuery.event.trigger() and        // when an event is called after a page has unloaded        return typeof jQuery !== "undefined" && jQuery.event.triggered !== e.type ?          jQuery.event.dispatch.apply( elem, arguments ) : undefined;      };    }    // 處理事件綁定，考慮到可能會通過空格分隔傳入多個事件，這里要進(jìn)行多事件處理    types = ( types || "" ).match( rnotwhite ) || [ "" ];    t = types.length;    while ( t-- ) {      tmp = rtypenamespace.exec( types[ t ] ) || [];       type = origType = tmp[ 1 ];      namespaces = ( tmp[ 2 ] || "" ).split( "." ).sort();      // There *must* be a type, no attaching namespace-only handlers      if ( !type ) {        continue;      }      // If event changes its type, use the special event handlers for the changed type      special = jQuery.event.special[ type ] || {};      // If selector defined, determine special event api type, otherwise given type      type = ( selector ? special.delegateType : special.bindType ) || type;      // Update special based on newly reset type      special = jQuery.event.special[ type ] || {};      // 事件回調(diào)函數(shù)的數(shù)據(jù)對象      handleObj = jQuery.extend( {        type: type,        origType: origType,        data: data,        handler: handler,        guid: handler.guid,        selector: selector,        needsContext: selector && jQuery.expr.match.needsContext.test( selector ),        namespace: namespaces.join( "." )      }, handleObjIn );      // 加入第一次綁定該類事件，會初始化一個數(shù)組作為事件回調(diào)函數(shù)隊列，每個元素的每一種事件有一個隊列      if ( !( handlers = events[ type ] ) ) {        handlers = events[ type ] = [];        handlers.delegateCount = 0;        // Only use addEventListener if the special events handler returns false        if ( !special.setup ||          special.setup.call( elem, data, namespaces, eventHandle ) === false ) {          if ( elem.addEventListener ) {            elem.addEventListener( type, eventHandle );          }        }      }      if ( special.add ) {        special.add.call( elem, handleObj );        if ( !handleObj.handler.guid ) {          handleObj.handler.guid = handler.guid;        }      }      // 加入到事件回調(diào)函數(shù)隊列      if ( selector ) {        handlers.splice( handlers.delegateCount++, 0, handleObj );      } else {        handlers.push( handleObj );      }      // Keep track of which events have ever been used, for event optimization      // 用來追蹤哪些事件從未被使用，用以優(yōu)化      jQuery.event.global[ type ] = true;    }  }};

handlers = events[ type ] = [];if ( selector ) {  handlers.splice( handlers.delegateCount++, 0, handleObj );} else {  handlers.push( handleObj );}

function Data() {  this.expando = jQuery.expando + Data.uid++;}Data.uid = 1;//刪除部分沒用到代碼Data.prototype = {  cache: function( owner ) {    // 取出緩存，可見緩存就是目標(biāo)對象的一個屬性    var value = owner[ this.expando ];    // 如果對象還沒有緩存，則創(chuàng)建一個    if ( !value ) {      value = {};      // We can accept data for non-element nodes in modern browsers,      // but we should not, see #8335.      // Always return an empty object.      if ( acceptData( owner ) ) {        // If it is a node unlikely to be stringify-ed or looped over        // use plain assignment        if ( owner.nodeType ) {          owner[ this.expando ] = value;        // Otherwise secure it in a non-enumerable property        // configurable must be true to allow the property to be        // deleted when data is removed        } else {          Object.defineProperty( owner, this.expando, {            value: value,            configurable: true          } );        }      }    }    return value;  },  get: function( owner, key ) {    return key === undefined ?      this.cache( owner ) :      // Always use camelCase key (gh-2257) 駝峰命名      owner[ this.expando ] && owner[ this.expando ][ jQuery.camelCase( key ) ];  },  remove: function( owner, key ) {    var i,      cache = owner[ this.expando ];    if ( cache === undefined ) {      return;    }    if ( key !== undefined ) {      // Support array or space separated string of keys      if ( jQuery.isArray( key ) ) {        // If key is an array of keys...        // We always set camelCase keys, so remove that.        key = key.map( jQuery.camelCase );      } else {        key = jQuery.camelCase( key );        // If a key with the spaces exists, use it.        // Otherwise, create an array by matching non-whitespace        key = key in cache ?          [ key ] :          ( key.match( rnotwhite ) || [] );      }      i = key.length;      while ( i-- ) {        delete cache[ key[ i ] ];      }    }    // Remove the expando if there's no more data    if ( key === undefined || jQuery.isEmptyObject( cache ) ) {      // Support: Chrome <=35 - 45      // Webkit & Blink performance suffers when deleting properties      // from DOM nodes, so set to undefined instead      // https://bugs.chromium.org/p/chromium/issues/detail?id=378607 (bug restricted)      if ( owner.nodeType ) {        owner[ this.expando ] = undefined;      } else {        delete owner[ this.expando ];      }    }  },  hasData: function( owner ) {    var cache = owner[ this.expando ];    return cache !== undefined && !jQuery.isEmptyObject( cache );  }};