user9477865
Reputation:
Get localStorage value on page load
I've searched the internet but I can't seem to find anything that works for me.
Here is the code:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Heating System Control</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script>
strLED1 = "";
strLED2 = "";
strText1 = "";
strText2 = "";
var LED1_state = 0;
var LED2_state = 0;
function GetArduinoIO()
{
nocache = "&nocache=" + Math.random() * 1000000;
var request = new XMLHttpRequest();
request.onreadystatechange = function()
{
if (this.readyState == 4) {
if (this.status == 200) {
if (this.responseXML != null)
{
// XML file received - contains analog values, switch values and LED states
document.getElementById("input1").innerHTML =
this.responseXML.getElementsByTagName('analog')[0].childNodes[0].nodeValue;
document.getElementById("input2").innerHTML =
this.responseXML.getElementsByTagName('analog')[1].childNodes[0].nodeValue;
// LED 1
if (this.responseXML.getElementsByTagName('LED')[0].childNodes[0].nodeValue === "on") {
document.getElementById("LED1").innerHTML = "ON";
document.getElementById("LED1").style.backgroundColor = "green";
document.getElementById("LED1").style.color = "white";
LED1_state = 1;
}
else {
document.getElementById("LED1").innerHTML = "OFF";
document.getElementById("LED1").style.backgroundColor = "red";
document.getElementById("LED1").style.color = "white";
LED1_state = 0;
}
// LED 2
if (this.responseXML.getElementsByTagName('LED')[1].childNodes[0].nodeValue === "on") {
document.getElementById("LED2").innerHTML = "ON";
document.getElementById("LED2").style.backgroundColor = "green";
document.getElementById("LED2").style.color = "white";
LED2_state = 1;
}
else {
document.getElementById("LED2").innerHTML = "OFF";
document.getElementById("LED2").style.backgroundColor = "red";
document.getElementById("LED2").style.color = "white";
LED2_state = 0;
}
}
}
}
}
// send HTTP GET request with LEDs to switch on/off if any
request.open("GET", "ajax_inputs" + strLED1 + strLED2 + nocache, true);
request.send(null);
setTimeout('GetArduinoIO()', 1000);
strLED1 = "";
strLED2 = "";
}
function GetButton1()
{
if (LED1_state === 1)
{
LED1_state = 0;
strLED1 = "&LED1=0";
}
else
{
LED1_state = 1;
strLED1 = "&LED1=1";
}
}
function GetButton2()
{
if (LED2_state === 1)
{
LED2_state = 0;
strLED2 = "&LED2=0";
}
else
{
LED2_state = 1;
strLED2 = "&LED2=1";
}
}
function SendText1()
{
nocache = "&nocache=" + Math.random() * 1000000;
var request = new XMLHttpRequest();
strText2 = "&txt2=" + document.getElementById("txt_form1").form_text1.value + "&end2=end";
request.open("GET", "ajax_inputs" + strText2 + nocache, true);
request.send(null);
}
function SendText2()
{
nocache = "&nocache=" + Math.random() * 1000000;
var request = new XMLHttpRequest();
strText1 = "&txt1=" + document.getElementById("txt_form2").form_text2.value + "&end1=end";
request.open("GET", "ajax_inputs" + strText1 + nocache, true);
request.send(null);
}
function clsTxt1()
{
setTimeout(
function clearTxt()
{
document.getElementById("txt_form1").form_text1.value = "";
}, 500)
}
function clsTxt2()
{
setTimeout(
function clearTxt()
{
document.getElementById("txt_form2").form_text2.value = "";
}, 500)
}
function Threshold1()
{
var thr1 = document.getElementById("txt_form1").form_text1.value;
document.getElementById("thresh1").innerHTML = thr1;
}
function Threshold2()
{
var thr2 = document.getElementById("txt_form2").form_text2.value;
document.getElementById("thresh2").innerHTML = thr2;
}
</script>
<style>
.IO_box
{
float: left;
margin: 0 20px 20px 0;
border: 1px solid black;
padding: 0 5px 0 5px;
width: 100px;
height: 196px;
text-align: center;
}
h1
{
font-family: Helvetica;
font-size: 120%;
color: blue;
margin: 5px 0 10px 0;
text-align: center;
}
h2
{
font-family: Helvetica;
font-size: 85%;
color: black;
margin: 10px 0 5px 0;
text-align: center;
}
p, form
{
font-family: Helvetica;
font-size: 80%;
color: #252525;
text-align: center;
}
button
{
font-family: Helvetica;
font-size: 80%;
max-width: 100px;
width: 90px;
height: 25px;
margin: 0 auto;
text-align: center;
border: none;
}
input
{
font-family: Helvetica;
font-size: 80%;
max-width: 100px;
width: 90px;
height: 25px;
margin: 0 auto;
text-align: center;
border: none;
}
.small_text
{
font-family: Helvetica;
font-size: 70%;
color: #737373;
text-align: center;
}
textarea
{
resize: none;
max-width: 90px;
margin-bottom: 1px;
text-align: center;
}
</style>
</head>
<body onload="GetArduinoIO(); Threshold1()">
<h1>Heating System Control</h1>
<div class="IO_box">
<h2>Room One</h2>
<p>Temp1 is: <span id="input1">...</span></p>
<button type="button" id="LED1" onclick="GetButton1()" color="white" backgroundColor="red" style="border: none;">OFF</button><br /><br />
<form id="txt_form1" name="frmText">
<textarea name="form_text1" rows="1" cols="10"></textarea>
</form>
<input type="submit" value="Set Temp" onclick="SendText1(); clsTxt1(); Threshold1();" style ="background-color:#5F9EA0" />
<p>Threshold: <span id="thresh1">...</span></p>
</div>
<div class="IO_box">
<h2>Room Two</h2>
<p>Temp2 is: <span id="input2">...</span></p>
<button type="button" id="LED2" onclick="GetButton2()" color="white" backgroundColor="red" style="border: none;">OFF</button><br /><br />
<form id="txt_form2" name="frmText">
<textarea name="form_text2" rows="1" cols="10"></textarea>
</form>
<input type="submit" value="Set Temp" onclick="SendText2(); clsTxt2(); Threshold2();" style ="background-color:#5F9EA0" />
<p>Threshold: <span id="thresh2">...</span></p>
</div>
</body>
</html>
So my question is, How can I keep the value inserted in the text area even after I reload the page (from the "Threshold1()" function)? I found a few examples with "localStorage" and JQuery, but I have no idea how to call the saved value when I reload the page.
Any help would be appreciated.
Thanks in advance, Stefan.
Upvotes: 3
Views: 10945
Answers (3)
user9477865
Reputation:
My question isn't exactly answered, but I completely avoided storing info on a device. Now I'm just reading the value straight from the arduino and it works. But thanks to everyone that provided some help.
Upvotes: 0
JO3-W3B-D3V
Reputation: 2134
Local Storage Explained
The localStorage object likes to store strings, so how would one store large objects, let's say some complex data structure? - Simple, JavaScript has a neat function built in, look up JSON.stringify(object). So all you would need to do is something like below to store some complex object is something like the code I've provided below. Then to retrieve an object from the localStorage you'll want to use JSON.parse(object);.
To look into localStorage, I strongly suggest you take a look at the likes of MDN and if you want to look into the JSON.parse and JSON.stringify functions, you can also find them both here:
// vanilla js version of $(document).ready(function(){/*code here*/});
window.ready = function(fnc) {
if (typeof fnc != "function") {
return console.error("You need to pass a function as a param.");
}
try { // try time out for some old IE bugs
setTimeout(function () {
document.addEventListener("DOMContentLoaded", fnc());
}, 10)
} catch (e) {
try { // sometimes timeout won't work
document.addEventListener("DOMContentLoaded", fnc());
} catch (ex) {
console.log(ex);
}
}
};
// shorter than $(document).ready();
ready(function() {
var object = {
name: "Jack",
age: 30,
location: "U.S.A.",
get_pay: function() {
console.log("test");
}
},
test;
console.log(object);
var obj_string = JSON.stringify(object);
// run a test
var run_test = function() {
// output the stored object
test = localStorage.getItem("test");
console.log(test);
// to make js turn it into an object again
test = JSON.parse(localStorage.getItem("test"));
console.log(test);
};
// demo of trying to store an actual object
try {
localStorage.setItem("test", object);
run_test();
} catch (e) {
console.log(e);
}
// demo of trying to store the string
try {
localStorage.setItem("test", obj_string);
run_test();
} catch (e) {
console.log(e);
}
});Upvotes: 2
Narendra Selot
Reputation: 24
You can use this JSFiddle : http://jsfiddle.net/xpvt214o/45115/
here we are using Cookie concept and jquery.cookie.js to accomplish what you are trying to do.
to properly check the fiddle you need to press "Run" every time, you can open the same fiddle in 2 tabs write something in the first fiddle then just press run in the 2nd fiddle tab the value should automatically update, here the
$(function(){}); replicates your pageload
Upvotes: 1
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