dom-events

How to do I validate a textarea in a form? i.e, it should not be empty or have any new lines, and if so raise an alert. Code: <script> function val() { //ifnewline found or blank raise an alert } </script> <form> <textarea name = "pt_text" rows = "8" cols = "8" class = "input" WRAP ></textarea> <input type=""button" onclick="val();" </form> The easiest way I could think of: function validate() { var val = document.getElementById('textarea').value; if (/^\s*$/g.test(val) || val.indexOf('\n') != -1) { alert('Wrong content!'); } } Sarfraz Try this: <textarea id="txt" name = "pt_text" rows = "8"

I've made a small script using some of the HTML5 files features, which allows you to select one or more files, and each time it will write the name of the file(s). Everything works as it should, only the event to detect the value change of the files input fire only once, so how can I make it fire every change and not only on the first change? By the way, here is what I made: http://tamir.netspot.co.il/html5/files/ It appears that the change event listener is being removed because you're using innerHTML to update the same element ( wrapper ) that the input itself is inside. So the contents of

These days, I have read some documents about setTimeout, setInterval. I have learned that the Javascript is a single thread which will only execute one piece of code per time. At the same time, if there is a event happens, it will be pushed into the event queue and block until appropriate time. I want to to know, when many events are blocked waiting to execute at the same time. Is these events have different priorities, so the high priority event will execute before the low ones. Or just a FIFO queue. setTimeout(fn1, 10); $(document).click(fn2); //will be called at 6ms; $.ajax({ajaxSuccess(fn3

My code // do ajax request and get JSON response for (var i = 0; i < data.results.length; i++) { result = data.results[i]; // do stuff and create google maps marker marker = new google.maps.Marker({ position: new google.maps.LatLng(result.lat, result.lng), map: map, id: result.id }); google.maps.event.addListener(marker, 'click', function() { createWindow(marker.id); //<==== this doesn't work because marker always points to the last results when this function is called }); } How to solve this? Try this: with ({ mark: marker }) { google.maps.event.addListener(mark, 'click', function() {

I'm only adding a click event handler on my <button> . document.getElementsByTagName("button")[0].addEventListener("click", event => { event.preventDefault(); console.log("Click:", event); }); <button>Press <kbd>Enter</kbd> on me</button> ( Demo link ) Nevertheless, when I tab to the button in Firefox, then press Enter , I see the click event being fired. However, I cannot see this behaviour documented anywhere. Is this standard behaviour, and can I count on it working in all browsers? This is largely because lots of authors have historically written code using click events while forgetting to

In JavaScript, for an event handler that needs access to private members and functions, I can rely on the function scope of those to be accessible within my event handler function, and do something like this: theElement.addEventListener("click", onClick); and later: theElement.removeEventListener("click", onClick); In TypeScript, I need to use an anonymous function to have this be the containing object, like so: theElement.addEventListener("click", (event) => this.onClick(event)); In this case, I can't remove the anonymous function from the listening to the event. How do I have an event

I am trying to build a Progressive Web App (PWA). The service worker shows registered, PWA audit shows everything good, but the console shows this error: TypeError: Request failed pwa error I am unable to cache the files. I tried all possible answers on Stack Overflow and it's the same //self.addEventListener('fetch', function(event) {}); var dataCacheName = 'myappData-v3n'; var cacheName = 'myapp-3n'; var filesToCache = [ 'images/logo.png', 'js/jquery.min.js', 'js/popper.min.js', 'js/bootstrap.min.js', 'js/main.js', 'css/bootstrap.min.css', 'css/fontawesome-all.min.css', 'css/style.css', 'css

I want to submit the form if Enter is pressed and stop the event if Shift + Enter is pressed. The callback for this has Ext.EventObject parameter which does not provide any way to check if shiftkey is pressed. it has two methods .hasModifier and .isSpecialKey . Both returns boolean . There is no way to find if shiftkey is pressed. how do I trace it? This is my textarea component: { region : 'center', margins : '5 0 0 0', xtype : 'textarea', name : 'chatmessage', enableKeyEvents: true, listeners: { keydown: function(textfield, evt, eOpts){ console.log(evt.getKey()); } } } I tried evt.shiftKey .