event-handling | 易学教程

javascript - button needs to be click twice for onclick to trigger

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问题 Why does my button need to be clicked twice for the onclick event to trigger? There're some other thread on stackoverflow with the same problem, but in all the thread i found, the original poster puts the event handler inside the function. It's not like that with my code. Html <body> <ul id="parentList"> <li>First child</li> <li>Second child</li> <li>Third child</li> <li>Forth child</li> <li>Fifth child</li> </ul> <button type="button" id="delete">Delete first child</button> </body> Script:

can't remove specific event handlers when attached to document with .on()

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问题 Here's a simple fiddle to demo my situation... http://jsfiddle.net/UnsungHero97/EM6mR/17/ What I'm doing is adding an event handler for current & future elements, using .on() . I want to be able to remove these event handlers for specific elements when something happens; in the case of the fiddle, when the radio button is selected, the event handler for the blue elements should be removed and clicking those elements should not do anything anymore. It doesn't seem to be working :( How do I

How to initiate resizing function (trigger handle drag) for resizable jQuery UI elements

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问题 Currently dynamically creating a resizable element on mousedown when I click the screen. jQuery UI auto adds handles to allow the user to click and drag to resize the element afterward. I would like to trigger the handle so that as long as the user hasn't triggered mouseup they'll already be resizing the newly created element. I can't find anything in the documentation that shows what events get triggered upon clicking those handles. I have tried executing mousedown and click on the handle

how to add an eventListener to an Object in javascript which will fire when object is manipulated?

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问题 I have a complicated UI structure which is manipulated dynamically, and say I have an ui_state object where i keep user's latest UI states such as which tab was visible, what was inside that tab etc. For instance: var ui_states = { tabs : [ { name : "some tab", active : true, children : { ... } }, { name : "some other tab", children : { ... } } ] } I keep this on html5 localStorage and when user refreshes the site it reopens the page the same. And everytime when the UI changes this object is

Cross browser disable the user select (Ctrl + A)

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问题 By default the user can drag and select the screen item / press CTRL + A ,all the item will be turn blue and blur (selected). However, is there any way to block this event? Thanks Are there any simple way just like adding some restriction in browser or adding some attribute in body tag can solve the problem? 回答1: user-select:none; -moz-user-select: none; -webkit-user-select: none; -ms-user-select: none; Add Following user-select property to that element which you do not want to turn blue.

Application / MVC Event Model

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问题 Update: This question was inspired by my larger quest for mapping ontologically the whole software systems architecture enchilada. I've written a blog post about it, and hopefully it will help clarify what I'm after. Many, many, many frameworks and stacks that's event-driven have too much variation for my little head to get around. Is there somewhere some resources that defines the outline of a reasonable Application Event Model, what events there are, and what triggers are most common? I've

How to implement Android message handler pattern in standard Java?

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问题 I'm writing an Android app that communicates with a PC via bluetooth. During normal operation, it sends out a rapid succession of short 8 byte packets from the Phone to the PC, typically at >100Hz. On each device, a separate thread is running that execute writes and reads. The code looks like this: /** * The Class ProcessConnectionThread. */ public class ConnectedThread extends Thread { /** The m connection. */ private StreamConnection mmConnection; InputStream mmInputStream; OutputStream

Delphi idle handler only fires when I move the mouse

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问题 I have an OnIdle handler in my D2006 app. With this code: procedure TMainForm.ApplicationEvents1Idle(Sender: TObject; var Done: Boolean); begin Inc (IdleCalls) ; Sleep (10) ; Done := False ; end ; the app runs smoothly, the idle handler is called 100 times per second, and the CPU usage is next to zero. I then added a TActionList and connected up some controls to actions, coded an Execute and Update handler. procedure TMainForm.ActionNewButtonExecute(Sender: TObject); begin DoNewProject ; end

How can I make the up and down arrow keys navigate a table's rows, and programmatically apply the sudo :hover to those rows?

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问题 I have an input of type text that is used to perform asynchronous table row searches using jquery. I have an .on function attached to the search input and on key down, I'm calling a function called hoverDown(). What I would like to happen when the down arrow key is pressed, is to hover over the table rows. And when a table row is hovered over with the arrow key, and the user hits enter, I would like for the href to fire and take the user to that related page. I am able to detect the e.keyCode

Handle system folders event in windows

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问题 I am writing some C# code and I need to detect if a specific folder on my windows file system has been opened while the application is running. Is there any way to do it? WinAPI maybe? 回答1: There are three API things I think you should check out: FindFirstChangeNotification() http://msdn.microsoft.com/en-us/library/aa364417%28VS.85%29.aspx That gives you a handle you can wait on and use to find changes to a file in a particular file, directory, or tree of directories. It won't tell you when a