Front End Technology Articles - Page 681 of 860

There are similar rules for native mobile apps and application. Only domain needs are to be added to white list in PhoneGap or Cardova.The device acts as a server and can access content from URL .If PhoneGap is used then domains are added to whitelist or a wildcard.While dealing with a native application, you expect to make requests from file://, instead of from https://. However, a request is not made across the HTTP protocol, so the same rules do not apply.Making requests from native mobile app, will allow you to make requests to any domain without any major issues. Read More

When we apply z index to a canvas whose position is fixed, it stop causes chrome to render all other elements which have position:fixed properly. This only happens if canvas is greater than 256X256 px in size.Wrap both h1 and canvas with the fixed div and solves the issue −    Test Title     The following is the CSS −h1{    position: fixed; } body{    height: 1500px; } canvas{    position: fixed; z-index: -10; }

One of the divs, when placed in another style sheet, can make menu invisible in Internet Explorer.If opacity property is used which is not a cross-border solution, it should be like the following to display −opaque {      -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=70)"; // first      filter: alpha(opacity=90);  // second }

In order to get latitude and longitude using an HTML5 Geolocation or any Google API, we need to add JavaScript for this. The script is as follows −if (navigator.geolocation) {    /*  If current position is obtained then there is success otherwise there is failure.    On failure, separate error message is shown  */        navigator.geolocation.getCurrentPosition(successFunc, errorFunc); }  else {        alert(‘Geolocation is not enabled in your browser. Please use a latest browser to supports it.'); }

Internet Explorer 8 and older versions does not support semantic elements like nav, header and article. To style semantic elements, Modernizer is used. Some CSS can be added to block CSS by default.article, header, nav, section, footer {    display:block; }We can also create our own elements through JavaScript by writing following code −    document.createElement('nav'); //nav is semantic element    document.createElement('header'); //header is semantic element    document.createElement('article'); //article is semantic element

When we have a requirement in which we want to track the latest locations for a user only when they are in a certain area, then we write separate code for it. The code to determine when to prompt the user to share location in HTML is as follows -if (frstTime) { //First time        navigator.getCurrentPosition(function (coordinates) {             if (coordsAreInTheBox) {                    storeCoordsForUser();                    navigator.watchPosition();             }        }); ... Read More

In order to speed up creation and edition of HTML, splitting of HTML files are required into three separate HTML files −HeaderFooterContentThis is not possible in a static Html website; however, this is possible through PHP. Another way is to use JavaScript to load page pieces after the main page is already loaded.

The event source is just a web socket that -That cannot send data Uses text or event stream format It fires events that are server definedIt is useful in applications that only need server push.Web sockets are good for applications that need fast communications in both directions.Another major difference is the different security models they used.Server Send events are useful for −Live Feeds Live Scores Stock Market Update

There is no description in HTML5 specification, which says deletion of a getContext property by the script is valid.We can write a code in which we delete getContext property of HTMLCanvasElement and then in the separate statement we make it undefined.Delete window.HTMLCanvasElement.prototype.getContext; _assertSame(window.HTMLCanvasElement.prototype.getContext, undefined,    "window.HTMLCanvasElement.prototype.getContext", "undefined");

When there is a requirement to pull down the screen to refresh the page to get latest updates, this can be done with the help of JavaScript, xhttprequests and then touch events.Pull refresh is a trigger to XHR in AJAX .It adds new data to the element we want.Pull refresh can be implemented with the help of hijacked JavaScript scrolling mechanism like iscroll. Twitter is using iscroll to pull refresh option.Another way is to create a refresh handler for overflow:scroll components.The interface provided can give an idea about the handler interface −var PullToRefresh= function(callback, wrapper, instructionsText) {    //It ... Read More