Javascript Articles - Page 553 of 671

The tag is used to add video, with the following video formats − MP4, WebM and OggOn selecting a file via the input element.The change event is firedThe event is fired for , , and elements when a change to the element's value is performed by the user.Getting File objectThe File interface provides information about files and allows JavaScript in a web page to access the content. Object of this type is returned by the files property of the HTML element, which eventually lets you access the list of files selected with the element.Object URL pointing ... Read More

For antialiasing, you need to set resampling quality.ctx.imageSmoothingQuality = "low|medium|high"Use an off-screen canvas to reduce the image to half −var c = document.createElement('canvas'), ocx = c.getContext('2d'); c.width = img.width * 0.5; c.height = img.height * 0.5; ocxx.drawImage(img, 0, 0, c.width, c.height);// drawing images reducing to half again and repeating itocx.drawImage(c, 0, 0, c.width * 0.5, cc.height * 0.5);

You can try to run the following code to draw an oval in HTML5 canvas −Example                                  // canvas          var c = document.getElementById('newCanvas');          var context = c.getContext('2d');          var cX = 0;          var cY = 0;          var radius = 40;                    context.save();          context.translate(c.width / 2, c.height / 2);          context.scale(2, 1);          context.beginPath();          context.arc(cX, cY, radius, 0, 2 * Math.PI, false);          context.restore();          context.fillStyle = '#000000';          context.fill();          context.lineWidth = 2;          context.strokeStyle = 'yellow';          context.stroke();           Output

localStorage is used to persist information across multiple sessions. It has a maximum size of 5MB.ExampleYou can try to run the following code snippet to check the size allocated −var sum = 0; // loop for size for(var i in localStorage) {    var amount = (localStorage[i].length * 2) / 1024 / 1024;    sum += amount;    document.write( i + " = " + amount.toFixed(2) + " MB"); } document.write( "Total = " + sum.toFixed(2) + " MB");

Html2Canvas is a JavaScript library that can take screenshot of the whole web page or specific part. It doesn’t take the screenshot but creates the view based on the page information.ExampleBelow given is an example code. Here, html2canvas.js script is included at the . The html2canvas() method is called. Returns the base64 value, which eventually creates image source or an image file.                         Take screenshot                                                      function screenshot(){             html2canvas(document.body).then(function(canvas) {                document.body.appendChild(canvas);             });          }          

For double buffering on the canvas, create a 2nd canvas element and draw to it. After that draw the image to the first canvas using the drawImage() method,// canvas element var canvas1 = document.getElementById('canvas'); var context1 = canvas1.getContext('2d'); // buffer canvas var canvas2 = document.createElement('canvas'); canvas2.width = 250; canvas2.height =250; var context2 = canvas2.getContext('2d'); // create on the canvas context2.beginPath(); context2.moveTo(10,10); context2.lineTo(10,30); context2.stroke(); //render the buffered canvas context1.drawImage(canvas2, 0, 0);

In Html, we can edit the content by using contenteditable attribute, it specifies whether the elements content is editable or not by the user. The property of contentEditable is set or returns if the content of an element is editable. Syntax The usage/syntax of editable content in HTML is − The above contenteditable attribute has two values true/false. True indicates that the element is editable. False indicates that the element cannot be edited. Example Following is the example, to create editable content in an HTML − This ... Read More

The HTML tag specifies set of options for element. You can try to run the following code to list options for input values in HTML5 −Example           HTML Datalist Tag                                                                                   Try to add any of the tutorial name mentioned above.    

The HTML tag is used to play music in the background. This tag is for Internet Explorer only.ExampleYou can try to run the following code to add background music in HTML −           HTML bgsound Tag                     Plays sound file in the background.     The HTML tag also supports the following attributes −AttributeValueDescriptionloopnumberLets you replay a background soundtrack a certain number of times.srcURLSpecifies the path of the sound file.

Use the dir attribute in HTML, to add the direction of the text.ExampleYou can try to run the following code to include the direction of text display in HTML −           This is demo text from left-to-right.       This is demo text from right-to-left.