jquery.fileupload-image-editor.js中

_initEventHandlers: function () {            this._super();            var handlers = {};            handlers[this.options.uploadImageEditorPreviewSelector] = this._previewHandler.bind(this);            this._on(this.options.filesContainer, handlers);        },

 

jquery.ui.widget.js

_on: function( suppressDisabledCheck, element, handlers ) {        var delegateElement,            instance = this;        // no suppressDisabledCheck flag, shuffle arguments        if ( typeof suppressDisabledCheck !== "boolean" ) {            handlers = element;            element = suppressDisabledCheck;            suppressDisabledCheck = false;        }        // no element argument, shuffle and use this.element        if ( !handlers ) {            handlers = element;            element = this.element;            delegateElement = this.widget();        } else {            element = delegateElement = $( element );            this.bindings = this.bindings.add( element );        }

 

遇到错误  

是因为找不到

uploadTemplateId: 'template-upload',

Uncaught TypeError: Cannot read property 'innerHTML' of null

at Function.tmpl.load (tmpl.js:38)

tmpl.load = function (id) {

return document.getElementById(id).innerHTML

}

at tmpl (tmpl.js:21)

var tmpl = function (str, data) {

var f = !/[^\w\-.:]/.test(str)

? (tmpl.cache[str] = tmpl.cache[str] || tmpl(tmpl.load(str)))

: new Function( // eslint-disable-line no-new-func

tmpl.arg + ',tmpl',

'var _e=tmpl.encode' +

tmpl.helper +

",_s='" +

str.replace(tmpl.regexp, tmpl.func) +

"';return _s;"

)

return data

? f(data, tmpl)

: function (data) {

return f(data, tmpl)

}

}

at $.<computed>.<computed>._initTemplates (jquery.fileupload-ui.js:657)

_initTemplates: function () {

var options = this.options;

options.templatesContainer = this.document[0].createElement(

options.filesContainer.prop('nodeName')

);

if (tmpl) {

if (options.uploadTemplateId) {

options.uploadTemplate = tmpl(options.uploadTemplateId);

}

if (options.downloadTemplateId) {

options.downloadTemplate = tmpl(options.downloadTemplateId);

}

}

}

at $.<computed>.<computed>._initTemplates (jquery.ui.widget.js:127)

at $.<computed>.<computed>._initSpecialOptions (jquery.fileupload-ui.js:677)

_initSpecialOptions: function () {

this._super();

this._initFilesContainer();

this._initTemplates();

},

at $.<computed>.<computed>._initSpecialOptions (jquery.ui.widget.js:127)

at $.<computed>.<computed>._create (jquery.fileupload.js:1381)

_create: function () {

this._initDataAttributes();

this._initSpecialOptions();

this._slots = [];

this._sequence = this._getXHRPromise(true);

this._sending = this._active = 0;

this._initProgressObject(this);

this._initEventHandlers();

},

at $.<computed>.<computed>._create (jquery.ui.widget.js:127)

at $.<computed>.<computed>._super (jquery.ui.widget.js:114)

at $.<computed>.<computed>._create (jquery.fileupload-process.js:167)

_create: function () {

this._super();

this._processing = 0;

this._processingQueue = $.Deferred().resolveWith(this)

.promise();

}

 

 

 

 

扩展阅读

_on( [suppressDisabledCheck ] [, element ], handlers )Returns: ()

Binds event handlers to the specified element(s). Delegation is supported via selectors inside the event names, e.g., "

click .foo". The

_on() method provides several benefits of direct event binding:

• Maintains proper this context inside the handlers.
• Automatically handles disabled widgets: If the widget is disabled or the event occurs on an element with the ui-state-disabled class, the event handler is not invoked. Can be overridden with the suppressDisabledCheck parameter.
• Event handlers are automatically namespaced and cleaned up on destroy.

• suppressDisabledCheck (default:

  false)
  Type:
  Whether or not to bypass the disabled check.
• element
  Type:
  Which element(s) to bind the event handlers to. If no element is provided,

  this.element is used for non-delegated events and is used for delegated events.
• handlers
  Type:
  An object in which the keys represent the event type and optional selector for delegation, and the values represent a handler function to be called for the event.

Code examples:

Prevent the default action of all links clicked within the widget's element.

this._on( this.element, {  "click a": function( event ) {    event.preventDefault();  }});

 

 

定义和用法

closest() 方法返回被选元素的第一个祖先元素。

祖先是父、祖父、曾祖父，依此类推。

DOM 树：该方法从当前元素向上遍历，直至文档根元素的所有路径（<html>），来查找 DOM 元素的第一个祖先元素。

该方法与  类似，都是向上遍历 DOM 树，不同点是：

closest()

• 从当前元素开始
• 沿 DOM 树向上遍历，并返回匹配所传递的表达式的第一个单一祖先
• 返回包含零个或一个元素的 jQuery 对象

parents()

• 从父元素开始
• 沿 DOM 树向上遍历，并返回匹配所传递的表达式的所有祖先
• 返回包含零个、一个或多个元素的 jQuery 对象