I'm using the table sorter from w3.js(https://www.w3schools.com/howto/howto_js_sort_table.asp).
Also, I have used setTimeout to refresh page per minute for updating data.
I want to keep the sorting result after refreshing page.
I know there's a method is using sessionStorage, but don't know how to use it.
Can anybody give me some tips?
Below is an updated snippet of the example in SortTable. We use the browser cookies to restore the last sort information, which are mainly the sorting column and direction. There is another example in W3school, from which I got the cookie handling (Cookies). The snippet below will not work here in the website because of the cross origin policy. Certainly, it also requires some refactoring, but it is a start.
<!DOCTYPE html>
<html>
<head>
<title>Sort a HTML Table Alphabetically</title>
<style>
table {
border-spacing: 0;
width: 100%;
border: 1px solid #ddd;
}
th {
cursor: pointer;
}
th, td {
text-align: left;
padding: 16px;
}
tr:nth-child(even) {
background-color: #f2f2f2
}
</style>
</head>
<body onload="checkCookie();">
<p><strong>Click the headers to sort the table.</strong></p>
<p>The first time you click, the sorting direction is ascending (A to Z).</p>
<p>Click again, and the sorting direction will be descending (Z to A):</p>
<table id="myTable">
<tr>
<!--When a header is clicked, run the sortTable function, with a parameter, 0 for sorting by names, 1 for sorting by country:-->
<th onclick="sortTable(0)">Name</th>
<th onclick="sortTable(1)">Country</th>
</tr>
<tr>
<td>Berglunds snabbkop</td>
<td>Sweden</td>
</tr>
<tr>
<td>North/South</td>
<td>UK</td>
</tr>
<tr>
<td>Alfreds Futterkiste</td>
<td>Germany</td>
</tr>
<tr>
<td>Koniglich Essen</td>
<td>Germany</td>
</tr>
<tr>
<td>Magazzini Alimentari Riuniti</td>
<td>Italy</td>
</tr>
<tr>
<td>Paris specialites</td>
<td>France</td>
</tr>
<tr>
<td>Island Trading</td>
<td>UK</td>
</tr>
<tr>
<td>Laughing Bacchus Winecellars</td>
<td>Canada</td>
</tr>
</table>
<script>
function sortTable(n, dir) {
var table, rows, switching, i, x, y, shouldSwitch, dir, switchcount = 0;
table = document.getElementById("myTable");
switching = true;
//Set the sorting direction to ascending:
!dir && (dir = "asc");
/*Make a loop that will continue until
no switching has been done:*/
while (switching) {
//start by saying: no switching is done:
switching = false;
rows = table.getElementsByTagName("TR");
/*Loop through all table rows (except the
first, which contains table headers):*/
for (i = 1; i < (rows.length - 1); i++) {
//start by saying there should be no switching:
shouldSwitch = false;
/*Get the two elements you want to compare,
one from current row and one from the next:*/
x = rows[i].getElementsByTagName("TD")[n];
y = rows[i + 1].getElementsByTagName("TD")[n];
/*check if the two rows should switch place,
based on the direction, asc or desc:*/
if (dir == "asc") {
if (x.innerHTML.toLowerCase() > y.innerHTML.toLowerCase()) {
//if so, mark as a switch and break the loop:
shouldSwitch= true;
break;
}
} else if (dir == "desc") {
if (x.innerHTML.toLowerCase() < y.innerHTML.toLowerCase()) {
//if so, mark as a switch and break the loop:
shouldSwitch= true;
break;
}
}
}
if (shouldSwitch) {
/*If a switch has been marked, make the switch
and mark that a switch has been done:*/
rows[i].parentNode.insertBefore(rows[i + 1], rows[i]);
switching = true;
//Each time a switch is done, increase this count by 1:
switchcount ++;
} else {
/*If no switching has been done AND the direction is "asc",
set the direction to "desc" and run the while loop again.*/
if (switchcount == 0 && dir == "asc") {
dir = "desc";
switching = true;
}
}
}
setCookie("sortBy", n, 30);
setCookie("sortByDir", dir);
}
function setCookie(cname,cvalue,exdays) {
var d = new Date();
d.setTime(d.getTime() + (exdays*24*60*60*1000));
var expires = "expires=" + d.toGMTString();
document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}
function getCookie(cname) {
var name = cname + "=";
var decodedCookie = decodeURIComponent(document.cookie);
var ca = decodedCookie.split(';');
for(var i = 0; i < ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') {
c = c.substring(1);
}
if (c.indexOf(name) == 0) {
return c.substring(name.length, c.length);
}
}
return "";
}
function checkCookie() {
var sortBy=getCookie("sortBy");
if (sortBy != "") {
sortTable(parseInt(sortBy), getCookie("sortByDir"));
}
}
</script>
</body>
</html>Edit: One more snippet to use sessionStorage instead
<!DOCTYPE html>
<html>
<head>
<title>Sort a HTML Table Alphabetically</title>
<style>
table {
border-spacing: 0;
width: 100%;
border: 1px solid #ddd;
}
th {
cursor: pointer;
}
th, td {
text-align: left;
padding: 16px;
}
tr:nth-child(even) {
background-color: #f2f2f2
}
</style>
</head>
<body onload="checkStrorage();">
<p><strong>Click the headers to sort the table.</strong></p>
<p>The first time you click, the sorting direction is ascending (A to Z).</p>
<p>Click again, and the sorting direction will be descending (Z to A):</p>
<table id="myTable">
<tr>
<!--When a header is clicked, run the sortTable function, with a parameter, 0 for sorting by names, 1 for sorting by country:-->
<th onclick="sortTable(0)">Name</th>
<th onclick="sortTable(1)">Country</th>
</tr>
<tr>
<td>Berglunds snabbkop</td>
<td>Sweden</td>
</tr>
<tr>
<td>North/South</td>
<td>UK</td>
</tr>
<tr>
<td>Alfreds Futterkiste</td>
<td>Germany</td>
</tr>
<tr>
<td>Koniglich Essen</td>
<td>Germany</td>
</tr>
<tr>
<td>Magazzini Alimentari Riuniti</td>
<td>Italy</td>
</tr>
<tr>
<td>Paris specialites</td>
<td>France</td>
</tr>
<tr>
<td>Island Trading</td>
<td>UK</td>
</tr>
<tr>
<td>Laughing Bacchus Winecellars</td>
<td>Canada</td>
</tr>
</table>
<script>
function sortTable(n, dir) {
var table, rows, switching, i, x, y, shouldSwitch, dir, switchcount = 0;
table = document.getElementById("myTable");
switching = true;
//Set the sorting direction to ascending:
!dir && (dir = "asc");
/*Make a loop that will continue until
no switching has been done:*/
while (switching) {
//start by saying: no switching is done:
switching = false;
rows = table.getElementsByTagName("TR");
/*Loop through all table rows (except the
first, which contains table headers):*/
for (i = 1; i < (rows.length - 1); i++) {
//start by saying there should be no switching:
shouldSwitch = false;
/*Get the two elements you want to compare,
one from current row and one from the next:*/
x = rows[i].getElementsByTagName("TD")[n];
y = rows[i + 1].getElementsByTagName("TD")[n];
/*check if the two rows should switch place,
based on the direction, asc or desc:*/
if (dir == "asc") {
if (x.innerHTML.toLowerCase() > y.innerHTML.toLowerCase()) {
//if so, mark as a switch and break the loop:
shouldSwitch= true;
break;
}
} else if (dir == "desc") {
if (x.innerHTML.toLowerCase() < y.innerHTML.toLowerCase()) {
//if so, mark as a switch and break the loop:
shouldSwitch= true;
break;
}
}
}
if (shouldSwitch) {
/*If a switch has been marked, make the switch
and mark that a switch has been done:*/
rows[i].parentNode.insertBefore(rows[i + 1], rows[i]);
switching = true;
//Each time a switch is done, increase this count by 1:
switchcount ++;
} else {
/*If no switching has been done AND the direction is "asc",
set the direction to "desc" and run the while loop again.*/
if (switchcount == 0 && dir == "asc") {
dir = "desc";
switching = true;
}
}
}
sessionStorage.setItem('sortBy', n);
sessionStorage.setItem('sortByDir', dir);
}
function checkStrorage() {
var sortBy= sessionStorage.getItem('sortBy');
if (sortBy !== null) {
sortTable(parseInt(sortBy), sessionStorage.getItem('sortByDir'));
}
}
</script>
</body>
</html>