jQuery.fn.extend({ data: function( key, value ) { var i, name, data, elem = this[ 0 ], attrs = elem && elem.attributes;return access( this, function( value ) { var data, camelKey = jQuery.camelCase( key ); // 从这里可以看出，为jQuery对象中的每个DOM元素分别附加数据 this.each(function() { // First, attempt to store a copy or reference of any // data that might've been store with a camelCased key. var data = dataUser.get( this, camelKey ); // For HTML5 data-* attribute interop, we have to // store property names with dashes in a camelCase form. // This might not apply to all properties...* dataUser.set( this, camelKey, value ); // *... In the case of properties that might _actually_ // have dashes, we need to also store a copy of that // unchanged property. if ( key.indexOf("-") !== -1 && data !== undefined ) { dataUser.set( this, key, value ); } }); }, null, value, arguments.length > 1, null, true ); }, removeData: function( key ) { return this.each(function() { dataUser.remove( this, key ); }); } });
上文中的所有源码：为jQuery.1.12