I want to make a counter remains dynamic and non-bootable when updating
web page,
here is my code the problem is that when I refresh the page the counter(setTimeout) will count again from zero to 5 I want it to count from the last value before
the refresh
<html>
<head>
<meta charset="utf-8"/>
<title>Insert title here</title>
</head>
<script type="text/javascript">
setTimeout(function(){document.getElementById("tm").style.display='block'},
5000);
</script>
<body>
<form id="customer" action="/htmlvalidation" method="post">
<div>
<label>Time</label>
<input id="tm" type="text" style="display: none;"/>
</div>
<div>
<button type="submit">Add Customer</button>
</div>
</form>
</body>
</html>
thank you
You will have to manually store the counter value in the client's browser; by default, browsers will not retain any of a webpage's state when it is closed (or refreshed). For example, you may use the localStorage API:
const STORAGE_KEY = 'counter';
const TARGET_ELEMENT_ID = 'counter-div';
const INTERVAL = 1000;
const INC = 1;
// Notice the '+' below to make sure val is a number.
let val = +localStorage.getItem(STORAGE_KEY) || 0;
document.getElementById(TARGET_ELEMENT_ID).innerHTML = val;
setInterval(() => {
val += INC;
localStorage.setItem(STORAGE_KEY, val);
document.getElementById(TARGET_ELEMENT_ID).innerHTML = val;
}, INTERVAL);
Here is a working example on codepen (it seems stackoverflow's snippets do not support localStorage).
(I didn't use your snippet because I wasn't sure what you were trying to do).
You could store the last timer iteration using localStorage before the user closes or navigates away from the tab, and resume when needed.
More about localStorage
Related
I want for the user to click a button which leads to another page. Depending on what button the user clicks, the page content should look different despite being on the same page. A simplified example is below:
Starting page html code:
<!DOCTYPE html>
<html>
<head>
</head>
<body>
Click Here
Click Here
<script src="script.js"></script>
</body>
</html>
second-page.html code:
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<p id="content-id">*CONTENT SHOULD BE LOADED HERE BASED OFF BUTTON CLICKED*</p>
<script src="script.js"></script>
</body>
</html>
script.js code:
function changeContent(n) {
document.getElementById("content-id").innerHTML = n;
}
The above code does not work. I'm guessing the browser doesn't see the content-id on the first page and fails to change anything before loading the second page. Any way to reference the right id on the right page using JavaScript (no jQuery) when the new page is loaded?
Short answer: there are several approaches, the easier that comes to mind is to use localStorage if you're dealing with same origin pages
What you need is to have user information available across multiple pages. So, unlike sessionStorage, localStorage allows to store data and save it across browser sessions:
localStorage is similar to sessionStorage, except that while localStorage data has no expiration time, sessionStorage data gets cleared when the page session ends — that is, when the page is closed.
To use it, consider adapting your javascript of first page:
function changeContent(n) {
localStorage.setItem('optionChosen', n);
}
Then retrieve it in the second page's javascript.
var opt = localStorage.getItem('optionChosen')
var content = document.querySelector('#content-id')
if (opt == null) console.log("Option null")
if (opt === 'Option One') content.innerText = "Foo"
if (opt === 'Option Two') content.innerText = "Bar"
Edited -
Added 3 working examples that can be copy and pasted.
Problem -
Display content on a new view based on the button clicked to get to that view.
Approach -
You can store the value of ID in the browser to help identify the content that should be displayed in many ways. I will show you three working examples.
Notes -
I am over complicating this a little to show you how you might make this work since I do not know the exact circumstances you are working with. You should be able to use this logic to refactor for your requirements. You will find the following 3 solutions below.
1. Using GET Params
Uses the GET params in the URL to help you track necessary changes in your view.
2. Using Session Storage
A page session lasts as long as the browser is open, and survives over page reloads and restores.
Opening a page in a new tab or window creates a new session with the value of the top-level browsing context, which differs from how session cookies work.
Opening multiple tabs/windows with the same URL creates sessionStorage for each tab/window.
Closing a tab/window ends the session and clears objects in sessionStorage.
3. Using Local Storage
The difference between localStorage and sessionStorage is the time the data persists. LocalStorage spans multiple windows and lasts beyond the current session.
The memory capacity may change by browser.
Similar to cookies, localStorage is not permanent. The data stored within it is specific to the user and their browser.
Solutions -
Working Examples - (Copy and paste any of the below solutions into an HTML file and they will work in your browser.)
Using GET Params
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width" />
<script type="text/javascript">
let currentURL = window.location.href.split("?")[0];
function appendParams(val) {
if (val === "a") {
window.location.assign(currentURL + "?id=a");
}
if (val === "b") {
window.location.assign(currentURL + "?id=b");
}
}
</script>
<title>Working Example</title>
</head>
<body>
<button onclick="appendParams('a')">Click Here</button>
<button onclick="appendParams('b')">Click Here</button>
<p id="replace-id"></p>
</body>
</html>
<script type="text/javascript">
let url_str = window.location.href;
let url = new URL(url_str);
let search_params = url.searchParams;
let id = search_params.get("id");
document.getElementById("replace-id").id = id;
let ContentOne = "Some text if id is A";
let ContentTwo = "Some text if id is B";
if (id === "a") {
document.getElementById("a").innerHTML = ContentOne;
}
if (id === "b") {
document.getElementById("b").innerHTML = ContentTwo;
}
</script>
Using Session Storage
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width" />
<script type="text/javascript">
sessionStorage.setItem("id", "default");
function addSessionStorage(val) {
sessionStorage.setItem("id", val);
updateContent();
}
function updateContent() {
let id = sessionStorage.getItem("id");
let ContentOne = "Some text if id is A";
let ContentTwo = "Some text if id is B";
if (id === "a") {
document.getElementById("replace-content").innerHTML =
ContentOne;
}
if (id === "b") {
document.getElementById("replace-content").innerHTML =
ContentTwo;
}
}
</script>
<title>Working Example</title>
</head>
<body>
<button onclick="addSessionStorage('a')">Click Here</button>
<button onclick="addSessionStorage('b')">Click Here</button>
<p id="replace-content">Default Content</p>
</body>
</html>
Using Local Storage
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width" />
<script type="text/javascript">
localStorage.setItem("id", "default");
function addLocalStorage(val) {
localStorage.setItem("id", val);
updateContent();
}
function updateContent() {
let id = localStorage.getItem("id");
let ContentOne = "Some text if id is A";
let ContentTwo = "Some text if id is B";
if (id === "a") {
document.getElementById("replace-content").innerHTML =
ContentOne;
}
if (id === "b") {
document.getElementById("replace-content").innerHTML =
ContentTwo;
}
}
</script>
<title>Working Example</title>
</head>
<body>
<button onclick="addLocalStorage('a')">Click Here</button>
<button onclick="addLocalStorage('b')">Click Here</button>
<p id="replace-content">Default Content</p>
</body>
</html>
I want to have a default value based on what the user put before. For example, if in an input I put '5' I want to see that the value of that input is 5 when I refresh the page, but if I put 6 I want the default value to be 6. Thanks (i'm a begginer)
Use local storage:
localStorage = window.localStorage;
localStorage.setItem('inputDefault', '5');
let inputDefault = localStorage.getItem('inputDefault');
Here's a more practical example I quickly whipped up:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Local Storage Example</title>
<script type="text/javascript">
function setLocalStorageValue()
{
let myNumberInputField = document.getElementById('myNumberInput');
let myNewValue = myNumberInputField.value;
let localStorage = window.localStorage;
localStorage.setItem('defaultValue', myNewValue);
}
function getLocalStoredValue()
{
let localStorage = window.localStorage;
let defaultValue = localStorage.getItem('defaultValue');
let myNumberInputField = document.getElementById('myNumberInput');
myNumberInputField.value = defaultValue;
}
</script>
</head>
<body onload="getLocalStoredValue()">
<label>My Number Input
<input type="number" id="myNumberInput" value="0" onchange="setLocalStorageValue()">
</label>
</body>
</html>
Does this answer your question? Note how I am writing back to local storage on the onchange event of the input in question, and I read from local storage when the body of the html loads.
I made a button click counter for a website using some JavaScript.
The counter works well, but now I'm stuck in making the saving of the count. You know, if I click the button 3 times, the text says 3 Times. But I want to save that value so if the user refreshes the page, it should display 3 Times again.
I knew of using localStorage, I followed a simple tutorial and applied it to my code, but it does not seem to be working. When I run the page in Microsoft Edge and see the Debug page (F12), the console throws an error that says: Unable to get property 'getItem' of undefined or null reference. I searched in other posts but no one of these could solve my problem. It seems to be stuck when retrieving the value in localStorage.
This is my code:
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Increment count when button is clicked</title>
</head>
<body>
<input type="button" value="Registrar" id="countButton" />
<input id="ocityField" type="text" value="" placeholder="Ciudad de Origen"/>
<input id="cityField" type="text" value="" placeholder="Ciudad de participación"/>
<input id="name" type="text" value="" placeholder="Nombre"/>
<p>Personas Registradas: <span id="displayCount">0</span></p>
<script type="text/javascript">
var count = 0;
var button = document.getElementById("countButton");
var display = document.getElementById("displayCount");
var textbox = document.getElementById("ocityField");
var textboxa = document.getElementById("cityField");
var textboxb = document.getElementById("name");
if(window.localStorage.getItem('count')){
var savedcount = window.localStorage.getItem('count');
count = window.localStorage.getItem('count');
}else{
count = 0;
}
display.innerHTML = count;
button.onclick = function(){
var mystring = textbox.value;
var mystring2 = textboxa.value;
var mystring3 = textboxb.value;
if(!mystring.match(/\S/) || !mystring2.match(/\S/) || !mystring3.match(/\S/)) {
alert ('Empty value is not allowed');
return false;
} else {
count++;
window.localStorage.setItem('count', count);
display.innerHTML = count;
textbox.value = "";
textboxa.value = "";
textboxb.value = "";
return true;
}
}
</script>
</body>
</html>
I tried using window.localStorage and just localStorage but no one did work.
May be that you use the IE browser does not support localStorage，The code can run in Chrome49.
Can I Use localStorage, here you can check what browser supports localStorage with version numbers.
Alternate way to store data on client side is cookies if localStorage doesn't supported by browser.
You can also use third party plugins like Modernizer, to check whether browser supports or not.
Modernizr.localstorage if it evaluate to true the browser supports localStorage.
Following example demonstrates localStorage and cookies depending on browser compatibility. uses Modernizer and jQuery
codepen
I'm trying to create a project which involves users being able to vote, and taking or adding to a global bank of points.
This is my very basic prototype, but I need to find a way to have the localstorage value be global, and the same for every user, using serverstorage.
The code:
<!DOCTYPE HTML>
<html>
<head>
<title>Javascript variable testing</title>
<script type="text/javascript">
var clicks;
function onClick() {
clicks = +clicks + 1;
document.getElementById("clicks").innerHTML = clicks;
localStorage.setItem('clicks', clicks); // set the value to localStorage
};
window.onload = function() {
clicks = localStorage.getItem('clicks') || 500000; // get the value from localStorage
document.getElementById("clicks").innerHTML = clicks;
};
</script>
</head>
<body>
<button type="button" onclick="onClick()">Click this bit</button>
<p>Clicks: <a id="clicks">500000</a>
</p>
</body>
</html>
localStorage is meant for storing data in the User's Browser. You might need to store data into your Server for your requirement. You can use AJAX for the same.
Is it possible to pass the totalScore var to another page onclick so that it can be displayed there? ex: click submit link it goes to yourscore.html and display the score on page
$("#process").click(function() {
var totalScore = 0;
$(".targetKeep").each( function(i, tK) {
if (typeof($(tK).raty('score')) != "undefined") {
totalScore += $(tK).raty('score');
}
});
alert("Total Score = "+totalScore);
});
Let we suppose that your HTML may be as follows:
<!DOCTYPE html>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("#process").click(function() {
var totalScore = 0;
/*
Your code to calculate Total Score
Remove the next line in real code.
*/
totalScore = 55; //Remove this
alert("Total Score = "+totalScore);
$("#submit-link").attr('href',"http://example.com/yourscore.html?totalScore="+totalScore);
});
});
</script>
<meta charset=utf-8 />
<title>JS Bin</title>
</head>
<body>
<button id="process">Process</button>
<br />
Submit Total Score
</body>
</html>
Check out this DEMO
In yourscore.html you may able to know more in the following queation to extract the URL parameter from the URL:
Parse URL with jquery/ javascript?
This is generally done by changing the url of the page. i.e. if you are going go to a new page, just do:
http://example.com/new/page?param1=test
If the page already exists in a new window (like a popup that you own), set the url to something new:
http://example.com/new/page#param
Open a window:
var win = window.open('http://example.com/new/page?totalscore'+totalscore,'window');
Change the location:
win.location.href='http://example.com/new/page?totalscore'+totalscore;
Other ways of doing this could be websockets or cookies or localstorage in HTML5.
if you are aiming to support more modern browsers the elegant solution could be to use sessionStorage or localStorage! Its extremely simple and can be cleared and set as you need it. The maximum size at the low end is 2mb but if your only storing INTs then you should be okay.
DOCS:
http://www.html5rocks.com/en/features/storage
http://dev.w3.org/html5/webstorage/
DEMO:
http://html5demos.com/storage
EXAMPLE:
addEvent(document.querySelector('#local'), 'keyup', function () {
localStorage.setItem('value', this.value);
localStorage.setItem('timestamp', (new Date()).getTime());
//GO TO YOUR NEXT PAGEHERE
});