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

When we draw anything on Canvas, it keeps no memory of anything that was drawn. While drawing we need to keep track of all the necessary information yourself as we draw. Therefore, it is not feasible to get value from HTML5 canvas to JavaScript as it keeps no memory. It just draws like this −On adding a function for button and clicking on it, you won’t be able to get what you want −     You will not be able to get those values from the canvas since the canvas is just a bitmap.

The arc() function has the following definition that shows the usage of start and ends angle −arc(x, y, radius, startAngle, endAngle, anticlockwise)This method has the following parameters −x and y are coordinates of the circle’s center.Radius is the circle radiusStartAngle and EndAngle define the start and endpoints of the arc in radians. Starting and closing angles are measured from the horizontal i.e. x-axisAnticlockwise is the Boolean value which when true draws arc anticlockwise otherwise in a clockwise direction.

Posts can be selected using div with ‘id=post’. This will select all div elements with an id which contains a value in quotes.We can use either −div[id*='post-'] { ... } or div[id^='post-'] { ... }.div[id*='post-'] { ... } will select all div elements with id which is having all values in quotes.Or we can use,div[id^='post-'] { ... }This will select all div elements with an id which started with quotes.