Messed Up Css for Chrome Then Couldnt Get Correct Position Back Again
User Location
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The Geolocation API lets yous discover, with the user'southward consent, the user'due south location. You can use this functionality for things like guiding a user to their destination and geo-tagging user-created content; for example, marking where a photo was taken.
The Geolocation API also lets you lot see where the user is and go along tabs on them as they move effectually, e'er with the user'south consent (and but while the page is open). This creates a lot of interesting use cases, such every bit integrating with backend systems to set an order for drove if the user is close past.
You need to be aware of many things when using the Geolocation API. This guide walks yous through the common apply cases and solutions.
TL;DR #
- Employ geolocation when it benefits the user.
- Ask for permission every bit a clear response to a user gesture.
- Use characteristic detection in example a user'southward browser doesn't back up geolocation.
- Don't but learn how to implement geolocation; learn the best way to apply geolocation.
- Test geolocation with your site.
When to use geolocation #
- Discover where the user is closest to a specific physical location to tailor the user experience.
- Tailor information (such as news) to the user'due south location.
- Show the position of a user on a map.
- Tag data created within your application with the user's location (that is, geo-tag a picture).
Ask permission responsibly #
Contempo user studies take shown that users are distrustful of sites that simply prompt the user to give away their position on page load. So what are the best practices?
Presume users will not requite yous their location #
Many of your users won't want to give you their location, so you need to adopt a defensive evolution style.
- Handle all errors out of the geolocation API so that you lot can arrange your site to this condition.
- Be clear and explicit about your need for the location.
- Apply a fallback solution if needed.
Employ a fallback if geolocation is required #
We recommend that your site or application non crave admission to the user's current location. However, if your site or application requires the user's current location, there are third-political party solutions that allow yous to obtain a best gauge of where the person currently is.
These solutions often work past looking at the user's IP address and mapping that to the physical addresses registered with the RIPE database. These locations are often not very accurate, unremarkably giving you the position of the telecommunications hub or jail cell phone tower that is nearest to the user. In many cases, they might not even be that accurate, especially if the user is on VPN or some other proxy service.
Always asking access to location on a user gesture #
Brand sure that users understand why you're asking for their location, and what the benefit to them will exist. Asking for it immediately on the homepage as the site loads results in a poor user experience.
Instead, give the user a articulate call to activity or an indication that an operation will require access to their location. The user tin can and then more easily associate the organization prompt for admission with the activity just initiated.
Requite a clear indication that an activity volition asking their location #
In a report past the Google Ads squad, when a user was asked to volume a hotel room in Boston for an upcoming briefing on one particular hotels site, they were prompted to share their GPS location immediately later tapping the "Find and Book" call to activity on the homepage.
In some cases, the user became frustrated because they didn't sympathise why they were being shown hotels in San Francisco when they wanted to volume a room in Boston.
A better feel is to make sure users understand why you're asking them for their location. Add a well-known signifier that is common across devices, such as a range finder, or an explicit call to action such equally "Find Near Me."
Gently nudge users to grant permission to their location #
You don't have admission to anything users are doing. You know exactly when users disallow access to their locations but you don't know when they grant you admission; you merely know you obtained access when results appear.
It's good do to "nudge" users into activeness if you need them to complete the action.
We recommend:
- Prepare up a timer that triggers later a short flow; 5 seconds is a good value.
- If you get an fault bulletin, evidence a message to the user.
- If you go a positive response, disable the timer and procedure the results.
- If, later on the timeout, you haven't gotten a positive response, show a notification to the user.
- If the response comes in afterward and the notification is still present, remove it from the screen.
button. onclick = function ( ) {
var startPos;
var nudge = document. getElementById ( 'nudge' ) ; var showNudgeBanner = part ( ) {
nudge.style.display = 'block' ;
} ;
var hideNudgeBanner = function ( ) {
nudge.style.display = 'none' ;
} ;
var nudgeTimeoutId = setTimeout (showNudgeBanner, 5000 ) ;
var geoSuccess = function ( position ) {
hideNudgeBanner ( ) ;
// We have the location, don't brandish banner
clearTimeout (nudgeTimeoutId) ;
// Do magic with location
startPos = position;
certificate. getElementById ( 'startLat' ) .innerHTML = startPos.coords.latitude;
document. getElementById ( 'startLon' ) .innerHTML = startPos.coords.longitude;
} ;
var geoError = function ( fault ) {
switch (error.code) {
instance error. TIMEOUT :
// The user didn't accept the callout
showNudgeBanner ( ) ;
intermission ;
}
} ;
navigator.geolocation. getCurrentPosition (geoSuccess, geoError) ;
} ;
Browser back up #
The majority of browsers at present support the Geolocation API but it'due south a good practise to always check for support before yous practise annihilation.
You tin hands check for compatibility past testing for the presence of the geolocation object:
// cheque for Geolocation support
if (navigator.geolocation) {
console. log ( 'Geolocation is supported!' ) ;
} else {
console. log ( 'Geolocation is not supported for this Browser/Os.' ) ;
} Determining the user's current location #
The Geolocation API offers a simple, "one-shot" method to obtain the user'southward location: getCurrentPosition(). A call to this method asynchronously reports on the user's current location.
window. onload = function ( ) {
var startPos;
var geoSuccess = part ( position ) {
startPos = position;
document. getElementById ( 'startLat' ) .innerHTML = startPos.coords.latitude;
document. getElementById ( 'startLon' ) .innerHTML = startPos.coords.longitude;
} ;
navigator.geolocation. getCurrentPosition (geoSuccess) ;
} ; If this is the first time that an application on this domain has requested permissions, the browser typically checks for user consent. Depending on the browser, in that location may also be preferences to always allow—or disallow—permission lookups, in which case the confirmation process is bypassed.
Depending on the location device your browser is using, the position object might actually contain a lot more than simply breadth and longitude; for instance, it might include an altitude or a direction. Yous can't tell what extra information that location organization uses until it actually returns the data.
Watching the user'southward location #
The Geolocation API allows you to obtain the user's location (with user consent) with a single telephone call to getCurrentPosition().
If you want to continually monitor the user's location, use the Geolocation API method, watchPosition(). It operates in a similar way to getCurrentPosition(), but information technology fires multiple times as the positioning software:
- Gets a more accurate lock on the user.
- Determines that the user's position is changing.
var watchId = navigator.geolocation. watchPosition ( office ( position ) {
certificate. getElementById ( 'currentLat' ) .innerHTML = position.coords.breadth;
document. getElementById ( 'currentLon' ) .innerHTML = position.coords.longitude;
} ) ; When to use geolocation to spotter the user'southward location #
- Yous desire to obtain a more precise lock on the user location.
- Your awarding needs to update the user interface based on new location information.
- Your awarding needs to update business organisation logic when the user enters a certain defined zone.
All-time practices when using geolocation #
Ever clear up and conserve battery #
Watching for changes to a geolocation is not a gratis operation. While operating systems might be introducing platform features to let applications hook in to the geo subsystem, yous, as a web developer, have no idea what back up the user's device has for monitoring the user's location, and, while you're watching a position, you are engaging the device in a lot of actress processing.
After you no longer demand to track the user'southward position, phone call clearWatch to plow off the geolocation systems.
Handle errors gracefully #
Unfortunately, not all location lookups are successful. Perhaps a GPS could not be located or the user has suddenly disabled location lookups. In the event of an mistake, a second, optional argument to getCurrentPosition() is chosen so that you tin can notify the user inside the callback:
window. onload = part ( ) {
var startPos;
var geoSuccess = part ( position ) {
startPos = position;
document. getElementById ( 'startLat' ) .innerHTML = startPos.coords.breadth;
document. getElementById ( 'startLon' ) .innerHTML = startPos.coords.longitude;
} ;
var geoError = function ( error ) {
console. log ( 'Error occurred. Error lawmaking: ' + mistake.lawmaking) ;
// error.lawmaking can be:
// 0: unknown error
// 1: permission denied
// 2: position unavailable (error response from location provider)
// three: timed out
} ;
navigator.geolocation. getCurrentPosition (geoSuccess, geoError) ;
} ; Reduce the need to start geolocation hardware #
For many apply cases, you don't demand the user's nearly up-to-date location; you only demand a rough estimate.
Use the maximumAge optional belongings to tell the browser to utilize a recently obtained geolocation result. This not only returns more than quickly if the user has requested the data earlier, only information technology also prevents the browser from starting its geolocation hardware interfaces such equally Wifi triangulation or the GPS.
window. onload = function ( ) {
var startPos;
var geoOptions = {
maximumAge : 5 * 60 * 1000 ,
} ; var geoSuccess = function ( position ) {
startPos = position;
document. getElementById ( 'startLat' ) .innerHTML = startPos.coords.latitude;
document. getElementById ( 'startLon' ) .innerHTML = startPos.coords.longitude;
} ;
var geoError = office ( fault ) {
console. log ( 'Error occurred. Error code: ' + fault.lawmaking) ;
// error.code can exist:
// 0: unknown error
// 1: permission denied
// 2: position unavailable (error response from location provider)
// 3: timed out
} ;
navigator.geolocation. getCurrentPosition (geoSuccess, geoError, geoOptions) ;
} ;
Don't keep the user waiting, fix a timeout #
Unless you set a timeout, your request for the current position might never render.
window. onload = function ( ) {
var startPos;
var geoOptions = {
timeout : ten * grand ,
} ; var geoSuccess = function ( position ) {
startPos = position;
document. getElementById ( 'startLat' ) .innerHTML = startPos.coords.latitude;
certificate. getElementById ( 'startLon' ) .innerHTML = startPos.coords.longitude;
} ;
var geoError = function ( error ) {
console. log ( 'Error occurred. Error code: ' + error.code) ;
// error.code can be:
// 0: unknown error
// i: permission denied
// two: position unavailable (mistake response from location provider)
// 3: timed out
} ;
navigator.geolocation. getCurrentPosition (geoSuccess, geoError, geoOptions) ;
} ;
Prefer a fibroid location over a fine-grained location #
If you desire to find the nearest store to a user, information technology's unlikely that yous need 1-meter precision. The API is designed to give a coarse location that returns as apace as possible.
If you do need a loftier level of precision, it'due south possible to override the default setting with the enableHighAccuracy pick. Use this sparingly: information technology's slower to resolve and uses more than battery.
window. onload = function ( ) {
var startPos;
var geoOptions = {
enableHighAccuracy : true ,
} ; var geoSuccess = office ( position ) {
startPos = position;
document. getElementById ( 'startLat' ) .innerHTML = startPos.coords.latitude;
document. getElementById ( 'startLon' ) .innerHTML = startPos.coords.longitude;
} ;
var geoError = function ( error ) {
console. log ( 'Error occurred. Error code: ' + error.code) ;
// error.code can be:
// 0: unknown error
// 1: permission denied
// two: position unavailable (error response from location provider)
// iii: timed out
} ;
navigator.geolocation. getCurrentPosition (geoSuccess, geoError, geoOptions) ;
} ;
One time you've got geolocation set up, you'll want to:
- Exam out how your app works in different geolocations.
- Verify that your app degrades gracefully when geolocation is non available.
You lot tin can exercise both from Chrome DevTools.
Open Chrome DevTools and then open the Console Drawer.
Open the Console Drawer card and click the Sensors option to testify the Sensors Drawer.
From here you lot can override the location to a preset major city, enter a custom location, or disable geolocation by setting the override to Location unavailable.
Feedback #
Last updated: — Improve commodity
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Source: https://developers.google.com/web/fundamentals/native-hardware/user-location
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