Javascript Articles - Page 445 of 534

Recreate the socket to reconnect it. The websockets are designed to stay open. You can also go with the method to have the server close the connection. Through this, the websocket will fire an onclose event and would amazingly continue attempting to make the connection.In addition, when the server is listening again the connection will be automatically reestablished.ExampleYou can try to run the following code to reconnect to WebSocket −// Socket Variable declaration var mySocket; const socketMessageListener = (event) => {    console.log(event.data); }; // Open const socketOpenListener = (event) => {    console.log('Connected');    mySocket.send('hello'); }; // Closed ... Read More

Use the pushSate object to update the page when the user navigates back through history. Let us see an example to include the selected color that creates a history entry −function display(color) {    var myState = { selectedColor: color },    myTitle = "Page title",    myPath = "/" + color;    history.pushState(myState, myTitle, myPath ); };Now we will use the popstate event to update the selected color −$(window).on('popstate', function(event) {    var myState = event.originalEvent.state;    if (statemyState {       selectColor( myState.selectedColor );    } });

For client-side processing and uploading, you can try to run the following code −

To achieve your goal for HTML5 Server-Sent Events −Try polyfillIt would work for IE10 and IE11 as well. It starts with −if ("EventSource" in global) return;It only runs in web browsers that do not support EventSource.Refer the following GitTry websockets Works for IE10 and IE 11 and it also provides bi-directional communication options.

To detect HTML5 audio MP3 support, use the Modernizr library.As stated in the official specification − Source − Screenshot from the official Modernizr documentation For detecting HTML5 audio MP3 support, you can also check the User-Agent to detect which browser is used.You can also use JavaScript to test −var x = document.createElement('audio'); return !!(x.canPlayType && x.canPlayType('audio/mpeg;').replace(/no/, ''));

For data-attribute typecasting of Numbers and String, use −[...document.querySelectorAll("a")].forEach(a =>    console.log("type: %s, value: %o", typeof a.dataset.value, a.dataset.value) );The above is for the following data-attributes −6.0 6.5

Use the JavaScript FileReader to allow users to choose an image.Let us see an example −         Here is the JS −function readURL(input) {    if (input.files && input.files[0]) {       var r = new FileReader();       r.onload = function (ev) {          $('#myid).attr('src', ev.target.result);       }       reader.readAsDataURL(input.files[0]);    } }   

To render thin fonts more smoothly, use −text-rendering: optimizeLegibility !important; -webkit-font-smoothing: antialiased !important; -moz-osx-font-smoothing: grayscale !important;For Google Chrome, use −-webkit-font-smoothing:antialiased !important;You can enhance the performance like this −text-rendering: auto text-rendering: optimizeSpeed text-rendering: optimizeLegibility text-rendering: geometricPrecision text-rendering: inherit

For viewport usage, use the drawImage() method.ctx.clearRect(0,0,game.width,game.height); // a full background image ctx.drawImage(background,cropLeft,cropTop,cropWidth,cropHeight, 0,0,viewWidth,viewHeight);For the game −var myGame = document.getElementById("game"); var myCtx= myGame.getContext("2d"); myCtx.clearRect(0,0,game.width,game.height); // using drawImage() method myCtx.drawImage(background,left,top,350,250,0,0,250,150); myCtx.beginPath(); myCtx.arc(130,80,12,0,Math.PI*2,false); myCtx.closePath(); myCtx.fill(); myCtx.stroke();

You need to track which elements dragenter and dragleave had been triggered on. Listening dragenter and dragleave on an individual element will capture not only events on that element but also events on children.$.fn.draghover = function(options) {    return this.each(function() {       var collection = $(),       self = $(this);       self.on('dragenter', function(ev) {          if (collection.length === 0) {             self.trigger('draghoverstart');          }          collection = collection.add(ev.target);       });       self.on('dragleave drop', function(ev) {          collection = collection.not(ev.target);          if (collection.length === 0) {             self.trigger('draghoverend');          }       });    }); };Listen for events −$(window).draghover().on({    'draghoverstart': function() {       alert(‘dragged into the window');    },    'draghoverend': function() {       alert('dragged out of window');    } });