Below is my script. It's a autosuggestion search script. The problem is that it penetrates the server with a huge amount of requests (it sends a request after each inserted character).
I need to change the script so that it waits 2 seconds after user has finished typing (and has inserted at least 3 characters) and only then sends request to the php file.
(function($){
$.fn.fsearch = function(){
var $searchInput = $(this);
$searchInput.after('<div id="divResult"></div>');
$resultDiv = $('#divResult');
$searchInput.focus();
$searchInput.addClass('searchi');
$resultDiv.html("<ul></ul><div id='search-footer' class='searchf'></div>");
$searchInput.keyup(function(e) {
var q=$(this).val();
if(q.length>2&&q.length<30){
var current_index = $('.selected').index(),
$options = $resultDiv.find('.option'),
items_total = $options.length;
$resultDiv.fadeIn();
$resultDiv.find('#search-footer').html("<img src='img/loader.gif' alt='Searching...'/>");
$.getJSON("/search.php",{searchword: q},function(jsonResult) {
var str='';
for(var i=0; i<jsonResult.length;i++)
{
str += '<li id=' + jsonResult[i].uid + ' class="option"><img class="profile_image" src="photos/'+jsonResult[i].media+'" alt="'+jsonResult[i].username+'"/><span class="name">' + jsonResult[i].username + '</span><br/>'+jsonResult[i].country+'</li>';
}
$resultDiv.find('ul').empty().prepend(str);
$resultDiv.find('div#search-footer').text(jsonResult.length + " results found...");
$resultDiv.find('ul li').first().addClass('selected');
});
$resultDiv.find('ul li').live('mouseover',function(e){
current_index = $resultDiv.find('ul li').index(this);
$options = $resultDiv.find('.option');
change_selection($options,current_index);
});
function change_selection($options,current_index){
$options.removeClass('selected');
$options.eq(current_index).addClass('selected');
}
} else{
$resultDiv.hide();
}
});
jQuery(document).live("click", function(e) {
var $clicked = $(e.target);
if ($clicked.hasClass("searchi") || $clicked.hasClass("searchf")){
}
else{
$resultDiv.fadeOut();
}
});
$searchInput.click(function(){
var q=$(this).val();
if(q.length>2&&q.length<30) {
$resultDiv.fadeIn();
}
});
$resultDiv.find('li').live("click",function(e){
var id = $(this).attr('id');
var name = ($(this).find('.name').text());
$searchInput.val(name);
});
};
})(jQuery);
After reading this question I added the following solution to my script:
var timer;
var x;
$(".some-input").keyup(function () {
if (x) { x.abort() } // If there is an existing XHR, abort it.
clearTimeout(timer); // Clear the timer so we don't end up with dupes.
timer = setTimeout(function() { // assign timer a new timeout
x = $.getJSON(...); // run ajax request and store in x variable (so we can cancel)
}, 2000); // 2000ms delay, tweak for faster/slower
});
unfortunately, it does not work:
TypeError: e.nodeName is undefined jquery-1.11.0.min.js:4:9004
I am using Jasmine for JS testing, and unfortunately I can't get the following test to pass.
it('should know the total game score', function() {
frame1 = new Frame;
frame2 = new Frame;
game = new Game;
frame1.score(3, 4);
frame2.score(5, 5);
expect(game.totalScore()).toEqual(17)
});
The error message I get is as follows: Error: Expected 0 to equal 17.
The code is as follows:
function Game() {
this.scorecard = []
};
Game.prototype.add = function(frame) {
this.scorecard.push(frame)
};
// Why is this not working!!???
Game.prototype.totalScore = function() {
total = 0;
for(i = 0; i < this.scorecard.length; i++)
{
total +=this.scorecard[i].rollOne + this.scorecard[i].rollTwo;
}
return total;
};
function Frame() {};
Frame.prototype.score = function(first_roll, second_roll) {
this.rollOne = first_roll;
this.rollTwo = second_roll;
return this
};
Frame.prototype.isStrike = function() {
return (this.rollOne === 10);
};
Frame.prototype.isSpare = function() {
return (this.rollOne + this.rollTwo === 10) && (this.rollOne !== 10)
};
Adding the numbers together manually seems to work e.g. total = game.scorecard[0].rollOne + this.scorecard[0].rollTwo , but the for loop (even though it looks correct) doesn't seem to work. Any help would be greatly appreciated :)
I am not pretty sure, but it seems that you are not calling the "Add" method, so no data is added to the scorecard.
You have to add the Frames to your game i guess
it('should know the total game score', function () {
frame1 = new Frame;
frame2 = new Frame;
game = new Game;
// those lines are missing
game.add(frame1);
game.add(frame2);
frame1.score(3, 4);
frame2.score(5, 5);
expect(17).toEqual(game.totalScore())
});
otherwise, the scorecard-array is empty and the total score is therefore equal to 0.
missing (so no data is added to the scorecard.)
game.Add(frame1);
game.Add(frame2);
I am trying to use JQuery's each() method to animate typing on multiple blocks of code, but I keep getting this error:
Uncaught TypeError: Cannot call method 'createDocumentFragment' of undefined
Check out some example code in this Fiddle...
And for your convenience, the JS is listed below:
$('.typeanimator').each(function(index) {
console.log(index);
var codeBlock = $(this).text();
var done;
var blockLength = codeBlock.length;
var charCounter = 0;
$(this).text('|');
(function typeAnimator() {
var typingSimulator = Math.round(Math.random() * (200));
done = setTimeout(function() {
console.log("Le print.");
charCounter++;
var typeSection = codeBlock.substring(0, charCounter);
$(this).text(typeSection + '|');
typeAnimator();
if (charCounter == blockLength) {
$(this).text($(this).text().slice(0, -1));
clearTimeout(done);
}
}, typingSimulator);
}());
});
The problem is in the use of $(this) inside the typeAnimator function. You are actually want to refer the this from the parent function but instead you are getting a totally different this. So, use a temporary variable to store the $(this)
$('.typeanimator').each(function(index) {
...
var self = $(this);
self.text('|');
(function typeAnimator() {
var typingSimulator = Math.round(Math.random() * (200));
done = setTimeout(function() {
...
self.text(typeSection + '|');
typeAnimator();
if (charCounter == blockLength) {
self.text(self.text().slice(0, -1));
clearTimeout(done);
}
}, typingSimulator);
}());
});
Updated fiddle
$('.typeanimator').each(function(index, current) {
console.log(index);
var codeBlock = $(current).text();
var done;
var blockLength = codeBlock.length;
var charCounter = 0;
$(current).text('|');
(function typeAnimator(context) {
var typingSimulator = Math.round(Math.random() * (200));
done = setTimeout(function() {
console.log("Le print.");
charCounter++;
var typeSection = codeBlock.substring(0, charCounter);
$(context).text(typeSection + '|');
typeAnimator(context);
if (charCounter == blockLength) {
$(context).text($(context).text().slice(0, -1));
clearTimeout(done);
}
}, typingSimulator);
}(current));
});
This should work, always remember that javascript is really picky about the context when using 'this'. As well .each() has nifty parameter of current item :) Gl, and good code.
I am creating some views in a loop iterating over list of objects. Now I want to register event with each view, which does something on the current object of the list.
for (var vs = 1; vs < 4; vs++) {
iMovie = moviesList[vs];
if (!iMovie) {
break;
}
var loopView = Ti.UI.createView({
....
});
loopView.addEventListener("click", function(e) {
var mv = iMovie;
Ti.API.info("Movie: " + mv);
if (mv) {
// do something
}
});
}
This code is not working, the log which is printed is : Movie: undefined.
So my question is how I can use the loop variable in the event listener?
Try the following code
var loopView - [];
var iMovie;
for (var vs = 1; vs < 4; vs++) {
iMovie = moviesList[vs];
if (!iMovie) {
break;
}
loopView[vs] = Ti.UI.createView({
_iMovie : iMovie
});
loopView[vs].addEventListener("click", function(e) {
var mv = e.source._iMovie;
Ti.API.info("Movie: " + mv);
if (mv) {
// do something
}
});
}
Well, first I'll start that what you are doing in the code above could potentially cause a memory leak since you are holding a reference to the iMovie variable.
what you should try doing is:
var mv = e.source;
this will return the source object that fired the click event.
How can I create a JavaScript page that will detect the user’s internet speed and show it on the page? Something like “your internet speed is ??/?? Kb/s”.
It's possible to some extent but won't be really accurate, the idea is load image with a known file size then in its onload event measure how much time passed until that event was triggered, and divide this time in the image file size.
Example can be found here: Calculate speed using javascript
Test case applying the fix suggested there:
//JUST AN EXAMPLE, PLEASE USE YOUR OWN PICTURE!
var imageAddr = "http://www.kenrockwell.com/contax/images/g2/examples/31120037-5mb.jpg";
var downloadSize = 4995374; //bytes
function ShowProgressMessage(msg) {
if (console) {
if (typeof msg == "string") {
console.log(msg);
} else {
for (var i = 0; i < msg.length; i++) {
console.log(msg[i]);
}
}
}
var oProgress = document.getElementById("progress");
if (oProgress) {
var actualHTML = (typeof msg == "string") ? msg : msg.join("<br />");
oProgress.innerHTML = actualHTML;
}
}
function InitiateSpeedDetection() {
ShowProgressMessage("Loading the image, please wait...");
window.setTimeout(MeasureConnectionSpeed, 1);
};
if (window.addEventListener) {
window.addEventListener('load', InitiateSpeedDetection, false);
} else if (window.attachEvent) {
window.attachEvent('onload', InitiateSpeedDetection);
}
function MeasureConnectionSpeed() {
var startTime, endTime;
var download = new Image();
download.onload = function () {
endTime = (new Date()).getTime();
showResults();
}
download.onerror = function (err, msg) {
ShowProgressMessage("Invalid image, or error downloading");
}
startTime = (new Date()).getTime();
var cacheBuster = "?nnn=" + startTime;
download.src = imageAddr + cacheBuster;
function showResults() {
var duration = (endTime - startTime) / 1000;
var bitsLoaded = downloadSize * 8;
var speedBps = (bitsLoaded / duration).toFixed(2);
var speedKbps = (speedBps / 1024).toFixed(2);
var speedMbps = (speedKbps / 1024).toFixed(2);
ShowProgressMessage([
"Your connection speed is:",
speedBps + " bps",
speedKbps + " kbps",
speedMbps + " Mbps"
]);
}
}
<h1 id="progress">JavaScript is turned off, or your browser is realllllly slow</h1>
Quick comparison with "real" speed test service showed small difference of 0.12 Mbps when using big picture.
To ensure the integrity of the test, you can run the code with Chrome dev tool throttling enabled and then see if the result matches the limitation. (credit goes to user284130 :))
Important things to keep in mind:
The image being used should be properly optimized and compressed. If it isn't, then default compression on connections by the web server might show speed bigger than it actually is. Another option is using uncompressible file format, e.g. jpg. (thanks Rauli Rajande for pointing this out and Fluxine for reminding me)
The cache buster mechanism described above might not work with some CDN servers, which can be configured to ignore query string parameters, hence better setting cache control headers on the image itself. (thanks orcaman for pointing this out))
The bigger the image size is, the better. Larger image will make the test more accurate, 5 mb is decent, but if you can use even a bigger one it would be better.
Well, this is 2017 so you now have Network Information API (albeit with a limited support across browsers as of now) to get some sort of estimate downlink speed information:
navigator.connection.downlink
This is effective bandwidth estimate in Mbits per sec. The browser makes this estimate from recently observed application layer throughput across recently active connections. Needless to say, the biggest advantage of this approach is that you need not download any content just for bandwidth/ speed calculation.
You can look at this and a couple of other related attributes here
Due to it's limited support and different implementations across browsers (as of Nov 2017), would strongly recommend read this in detail
I needed a quick way to determine if the user connection speed was fast enough to enable/disable some features in a site I’m working on, I made this little script that averages the time it takes to download a single (small) image a number of times, it's working pretty accurately in my tests, being able to clearly distinguish between 3G or Wi-Fi for example, maybe someone can make a more elegant version or even a jQuery plugin.
var arrTimes = [];
var i = 0; // start
var timesToTest = 5;
var tThreshold = 150; //ms
var testImage = "http://www.google.com/images/phd/px.gif"; // small image in your server
var dummyImage = new Image();
var isConnectedFast = false;
testLatency(function(avg){
isConnectedFast = (avg <= tThreshold);
/** output */
document.body.appendChild(
document.createTextNode("Time: " + (avg.toFixed(2)) + "ms - isConnectedFast? " + isConnectedFast)
);
});
/** test and average time took to download image from server, called recursively timesToTest times */
function testLatency(cb) {
var tStart = new Date().getTime();
if (i<timesToTest-1) {
dummyImage.src = testImage + '?t=' + tStart;
dummyImage.onload = function() {
var tEnd = new Date().getTime();
var tTimeTook = tEnd-tStart;
arrTimes[i] = tTimeTook;
testLatency(cb);
i++;
};
} else {
/** calculate average of array items then callback */
var sum = arrTimes.reduce(function(a, b) { return a + b; });
var avg = sum / arrTimes.length;
cb(avg);
}
}
As I outline in this other answer here on StackOverflow, you can do this by timing the download of files of various sizes (start small, ramp up if the connection seems to allow it), ensuring through cache headers and such that the file is really being read from the remote server and not being retrieved from cache. This doesn't necessarily require that you have a server of your own (the files could be coming from S3 or similar), but you will need somewhere to get the files from in order to test connection speed.
That said, point-in-time bandwidth tests are notoriously unreliable, being as they are impacted by other items being downloaded in other windows, the speed of your server, links en route, etc., etc. But you can get a rough idea using this sort of technique.
Even though this is old and answered, i´d like to share the solution i made out of it 2020 base on Shadow Wizard Says No More War´s solution
I just merged it into an object that comes with the flexibility to run at anytime and run a callbacks if the specified mbps is higher or lower the measurement result.
you can start the test anywhere after you included the testConnectionSpeed Object by running the
/**
* #param float mbps - Specify a limit of mbps.
* #param function more(float result) - Called if more mbps than specified limit.
* #param function less(float result) - Called if less mbps than specified limit.
*/
testConnectionSpeed.run(mbps, more, less)
for example:
var testConnectionSpeed = {
imageAddr : "https://upload.wikimedia.org/wikipedia/commons/a/a6/Brandenburger_Tor_abends.jpg", // this is just an example, you rather want an image hosted on your server
downloadSize : 2707459, // Must match the file above (from your server ideally)
run:function(mbps_max,cb_gt,cb_lt){
testConnectionSpeed.mbps_max = parseFloat(mbps_max) ? parseFloat(mbps_max) : 0;
testConnectionSpeed.cb_gt = cb_gt;
testConnectionSpeed.cb_lt = cb_lt;
testConnectionSpeed.InitiateSpeedDetection();
},
InitiateSpeedDetection: function() {
window.setTimeout(testConnectionSpeed.MeasureConnectionSpeed, 1);
},
result:function(){
var duration = (endTime - startTime) / 1000;
var bitsLoaded = testConnectionSpeed.downloadSize * 8;
var speedBps = (bitsLoaded / duration).toFixed(2);
var speedKbps = (speedBps / 1024).toFixed(2);
var speedMbps = (speedKbps / 1024).toFixed(2);
if(speedMbps >= (testConnectionSpeed.max_mbps ? testConnectionSpeed.max_mbps : 1) ){
testConnectionSpeed.cb_gt ? testConnectionSpeed.cb_gt(speedMbps) : false;
}else {
testConnectionSpeed.cb_lt ? testConnectionSpeed.cb_lt(speedMbps) : false;
}
},
MeasureConnectionSpeed:function() {
var download = new Image();
download.onload = function () {
endTime = (new Date()).getTime();
testConnectionSpeed.result();
}
startTime = (new Date()).getTime();
var cacheBuster = "?nnn=" + startTime;
download.src = testConnectionSpeed.imageAddr + cacheBuster;
}
}
// start test immediatly, you could also call this on any event or whenever you want
testConnectionSpeed.run(1.5, function(mbps){console.log(">= 1.5Mbps ("+mbps+"Mbps)")}, function(mbps){console.log("< 1.5Mbps("+mbps+"Mbps)")} )
I used this successfuly to load lowres media for slow internet connections. You have to play around a bit because on the one hand, the larger the image, the more reasonable the test, on the other hand the test will take way much longer for slow connection and in my case I especially did not want slow connection users to load lots of MBs.
The image trick is cool but in my tests it was loading before some ajax calls I wanted to be complete.
The proper solution in 2017 is to use a worker (http://caniuse.com/#feat=webworkers).
The worker will look like:
/**
* This function performs a synchronous request
* and returns an object contain informations about the download
* time and size
*/
function measure(filename) {
var xhr = new XMLHttpRequest();
var measure = {};
xhr.open("GET", filename + '?' + (new Date()).getTime(), false);
measure.start = (new Date()).getTime();
xhr.send(null);
measure.end = (new Date()).getTime();
measure.len = parseInt(xhr.getResponseHeader('Content-Length') || 0);
measure.delta = measure.end - measure.start;
return measure;
}
/**
* Requires that we pass a base url to the worker
* The worker will measure the download time needed to get
* a ~0KB and a 100KB.
* It will return a string that serializes this informations as
* pipe separated values
*/
onmessage = function(e) {
measure0 = measure(e.data.base_url + '/test/0.bz2');
measure100 = measure(e.data.base_url + '/test/100K.bz2');
postMessage(
measure0.delta + '|' +
measure0.len + '|' +
measure100.delta + '|' +
measure100.len
);
};
The js file that will invoke the Worker:
var base_url = PORTAL_URL + '/++plone++experimental.bwtools';
if (typeof(Worker) === 'undefined') {
return; // unsupported
}
w = new Worker(base_url + "/scripts/worker.js");
w.postMessage({
base_url: base_url
});
w.onmessage = function(event) {
if (event.data) {
set_cookie(event.data);
}
};
Code taken from a Plone package I wrote:
https://github.com/collective/experimental.bwtools/blob/master/src/experimental/bwtools/browser/static/scripts/
It's better to use images for testing the speed. But if you have to deal with zip files, the below code works.
var fileURL = "your/url/here/testfile.zip";
var request = new XMLHttpRequest();
var avoidCache = "?avoidcache=" + (new Date()).getTime();;
request.open('GET', fileURL + avoidCache, true);
request.responseType = "application/zip";
var startTime = (new Date()).getTime();
var endTime = startTime;
request.onreadystatechange = function () {
if (request.readyState == 2)
{
//ready state 2 is when the request is sent
startTime = (new Date().getTime());
}
if (request.readyState == 4)
{
endTime = (new Date()).getTime();
var downloadSize = request.responseText.length;
var time = (endTime - startTime) / 1000;
var sizeInBits = downloadSize * 8;
var speed = ((sizeInBits / time) / (1024 * 1024)).toFixed(2);
console.log(downloadSize, time, speed);
}
}
request.send();
This will not work very well with files < 10MB. You will have to run aggregated results on multiple download attempts.
thanks to Punit S answer, for detecting dynamic connection speed change, you can use the following code :
navigator.connection.onchange = function () {
//do what you need to do ,on speed change event
console.log('Connection Speed Changed');
}
Improving upon John Smith's answer, a nice and clean solution which returns a Promise and thus can be used with async/await. Returns a value in Mbps.
const imageAddr = 'https://upload.wikimedia.org/wikipedia/commons/a/a6/Brandenburger_Tor_abends.jpg';
const downloadSize = 2707459; // this must match with the image above
let startTime, endTime;
async function measureConnectionSpeed() {
startTime = (new Date()).getTime();
const cacheBuster = '?nnn=' + startTime;
const download = new Image();
download.src = imageAddr + cacheBuster;
// this returns when the image is finished downloading
await download.decode();
endTime = (new Date()).getTime();
const duration = (endTime - startTime) / 1000;
const bitsLoaded = downloadSize * 8;
const speedBps = (bitsLoaded / duration).toFixed(2);
const speedKbps = (speedBps / 1024).toFixed(2);
const speedMbps = (speedKbps / 1024).toFixed(2);
return Math.round(Number(speedMbps));
}
I needed something similar, so I wrote https://github.com/beradrian/jsbandwidth. This is a rewrite of https://code.google.com/p/jsbandwidth/.
The idea is to make two calls through Ajax, one to download and the other to upload through POST.
It should work with both jQuery.ajax or Angular $http.
//JUST AN EXAMPLE, PLEASE USE YOUR OWN PICTURE!
var imageAddr = "https://i.ibb.co/sPbbkkZ/pexels-lisa-1540258.jpg";
var downloadSize = 10500000; //bytes
function ShowProgressMessage(msg) {
if (console) {
if (typeof msg == "string") {
console.log(msg);
} else {
for (var i = 0; i < msg.length; i++) {
console.log(msg[i]);
}
}
}
var oProgress = document.getElementById("progress");
if (oProgress) {
var actualHTML = (typeof msg == "string") ? msg : msg.join("<br />");
oProgress.innerHTML = actualHTML;
}
}
function InitiateSpeedDetection() {
ShowProgressMessage("Loading the image, please wait...");
window.setTimeout(MeasureConnectionSpeed, 1);
};
if (window.addEventListener) {
window.addEventListener('load', InitiateSpeedDetection, false);
} else if (window.attachEvent) {
window.attachEvent('onload', InitiateSpeedDetection);
}
function MeasureConnectionSpeed() {
var startTime, endTime;
var download = new Image();
download.onload = function () {
endTime = (new Date()).getTime();
showResults();
}
download.onerror = function (err, msg) {
ShowProgressMessage("Invalid image, or error downloading");
}
startTime = (new Date()).getTime();
var cacheBuster = "?nnn=" + startTime;
download.src = imageAddr + cacheBuster;
function showResults() {
var duration = (endTime - startTime) / 1000;
var bitsLoaded = downloadSize * 8;
var speedBps = (bitsLoaded / duration).toFixed(2);
var speedKbps = (speedBps / 1024).toFixed(2);
var speedMbps = (speedKbps / 1024).toFixed(2);
ShowProgressMessage([
"Your connection speed is:",
speedBps + " bps",
speedKbps + " kbps",
speedMbps + " Mbps"
]);
}
}
<h1 id="progress">JavaScript is turned off, or your browser is realllllly slow</h1>
Mini snippet:
var speedtest = {};
function speedTest_start(name) { speedtest[name]= +new Date(); }
function speedTest_stop(name) { return +new Date() - speedtest[name] + (delete
speedtest[name]?0:0); }
use like:
speedTest_start("test1");
// ... some code
speedTest_stop("test1");
// returns the time duration in ms
Also more tests possible:
speedTest_start("whole");
// ... some code
speedTest_start("part");
// ... some code
speedTest_stop("part");
// returns the time duration in ms of "part"
// ... some code
speedTest_stop("whole");
// returns the time duration in ms of "whole"