A callback is procedure you pass as an argument to another procedure. The procedure receiving the parameter can call it, or share it so some other procedures in the system can call it. An event handler is a procedure called when an event happens. It can be a callback.
is the ajax uploader refreshing your input element? if so you should consider using .live() method. $(‘#imageFile’).live(‘change’, function(){ uploadFile(); }); update: from jQuery 1.7+ you should use now .on() $(parent_element_selector_here or document ).on(‘change’,’#imageFile’ , function(){ uploadFile(); });
The sender is the control that the action is for (say OnClick, it’s the button). The EventArgs are arguments that the implementor of this event may find useful. With OnClick it contains nothing good, but in some events, like say in a GridView ‘SelectedIndexChanged’, it will contain the new index, or some other useful data. … Read more
Here’s another solution that is very simple and doesn’t require you to worry about the finger being moved. If you are basing a click as simply the distance moved then how can you differentiate a click and a long click. You could put more smarts into this and include the distance moved, but i’m yet … Read more
You need to create an event handler for the user control that is raised when an event from within the user control is fired. This will allow you to bubble the event up the chain so you can handle the event from the form. When clicking Button1 on the UserControl, i’ll fire Button1_Click which triggers … Read more
You need to use the Observer Pattern. In the following code, a person subscribes to receive updates from the global wealth entity. When there is a change to global wealth, this entity then alerts all its subscribers (observers) that a change happened. Person then updates itself. I make use of properties in this example, but … Read more
You can’t. You have to use a named function or store the reference somehow. var handler; function doSomethingWith(param) { handler = function(){ document.write(param); }; document.body.addEventListener(‘scroll’, handler,false); } setTimeout(function() { document.body.removeEventListener(‘scroll’, handler ,false); }, 3000); The best would be to do this in a structured way, so that you can identify different handlers and remove them. … Read more
Google Custom Search Engines use a timer to check the hash against a previous value, whilst the child iframe on a seperate domain updates the parent’s location hash to contain the size of the iframe document’s body. When the timer catches the change, the parent can resize the iframe to match that of the body … Read more
The W3C Document Object Model Events Specification in 1.3.1. Event registration interfaces states that handleEvent in the EventListener has no return value: handleEvent This method is called whenever an event occurs of the type for which the EventListener interface was registered. […] No Return Value under 1.2.4. Event Cancelation the document also states that Cancelation … Read more
You can set the maxLength property for limiting the text in text box. Instead of onChange method you can pass maxLength to the inputProps (lowercase i, not InputProps) props of material-ui TextField. <TextField required id=”required” label=”Required” defaultValue=”Hello World” inputProps={{ maxLength: 12 }} /> Basically we can edit all input element’s native attrs via inputProps object. … Read more