So I'm rather new to JavaScript and I would love some help getting this code to work. I've looked at multiple other posts talking about session storage as well as if/else statements and still can't seem to figure it out.
I have a page, lets call it page 1 and it has 3 links, "red" "green" and "blue".
When you click on any of these links its function sets a session storage variable 'colorVar' to the color chosen and then redirects to a page called page 2.
As page 2 loads, the window.onload action is used to start a function according to the variable set on page 1. In this case the function that starts on page 2 simply displays "Your color is ____!".
Heres the code:
<!-- [This is Page 1] -->
<a href="Page2.html" onclick="colorRed()">Set color to red</a>
<a href="Page2.html" onclick="colorBlue()">Set color to blue</a>
<a href="Page2.html" onclick="colorGreen()">Set color to green</a>
<script>
function colorRed() {
sessionStorage.setItem("colorVar", "red");
}
function colorBlue() {
sessionStorage.setItem("colorVar", "blue");
}
function colorGreen() {
sessionStorage.setItem("colorVar", "green");
}
</script>
<!-- [This is Page 2] -->
<script>
window.onload = sessionStorage.colorVar + 'Write()';
function redWrite() {
document.write("Your color is red!")
}
function blueWrite() {
document.write("Your color is blue!")
}
function greenWrite() {
document.write("Your color is green!")
}
</script>
So I'm rather new to JavaScript and I would love some help getting this code to work. I've looked at multiple other posts talking about session storage as well as if/else statements and still can't seem to figure it out.
I have a page, lets call it page 1 and it has 3 links, "red" "green" and "blue".
When you click on any of these links its function sets a session storage variable 'colorVar' to the color chosen and then redirects to a page called page 2.
As page 2 loads, the window.onload action is used to start a function according to the variable set on page 1. In this case the function that starts on page 2 simply displays "Your color is ____!".
Heres the code:
<!-- [This is Page 1] -->
<a href="Page2.html" onclick="colorRed()">Set color to red</a>
<a href="Page2.html" onclick="colorBlue()">Set color to blue</a>
<a href="Page2.html" onclick="colorGreen()">Set color to green</a>
<script>
function colorRed() {
sessionStorage.setItem("colorVar", "red");
}
function colorBlue() {
sessionStorage.setItem("colorVar", "blue");
}
function colorGreen() {
sessionStorage.setItem("colorVar", "green");
}
</script>
<!-- [This is Page 2] -->
<script>
window.onload = sessionStorage.colorVar + 'Write()';
function redWrite() {
document.write("Your color is red!")
}
function blueWrite() {
document.write("Your color is blue!")
}
function greenWrite() {
document.write("Your color is green!")
}
</script>
- Opening a page in a new tab or window will cause a new session to be initiated. See more at developer.mozilla/en-US/docs/Web/API/Window/sessionStorage – Maria Ines Parnisari Commented Jun 26, 2016 at 2:16
- Hmm, wouldn't session storage still work if 'Page 2' was opened in the same tab as Page 1, or does this also cause a new session to be initiated? – Taylor Commented Jun 26, 2016 at 2:22
- 1 It wouldn't work. You should use local storage. – Maria Ines Parnisari Commented Jun 26, 2016 at 2:22
- Why don't you give the variable per URL? – user2628521 Commented Jun 26, 2016 at 2:35
3 Answers
Reset to default 2You can pass sessionStorage as as query string at href of <a> element; use location.search at window.onload event at Page2.html
Page1.html
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="style.css">
<script src="script.js"></script>
</head>
<body>
<a href="Page2.html" data-color="red" onclick="color(this)">Set color to red</a>
<a href="Page2.html" data-color="blue" onclick="color(this)">Set color to blue</a>
<a href="Page2.html" data-color="green" onclick="color(this)">Set color to green</a>
<script>
function color(elem) {
event.preventDefault();
sessionStorage.setItem("colorVar", elem.dataset.color);
location.href = elem.href + "?colorVar=" + sessionStorage.getItem("colorVar");
}
</script>
</body>
</html>
at Page2.html
<script>
window.onload = function() {
document.write("Your color is " + location.search.split("=").pop())
}
</script>
plnkr http://plnkr.co/edit/eNVXr4ElXRzrxlZ7EY0a?p=preview
Edit: Clearly the answer above is much better than what i provided. I'll leave this here for future viewers - maybe the way I phrased things help someone sometime.
Taylor,
Two things.
sessionStorage()is unique to each page/tab. From the docs "Opening a page in a new tab or window will cause a new session to be initiated"window.onloadis expecting a function. You're just concatenating a string.
If you find a different way to pass information from one page to another (you could stuff it in the URL) your new color function should look something like this:
<script>
window.onload = writeColor(sessionStorage.colorVar);
function writeColor(color) {
document.write("Your color is " + color + "!")
}
</script>
You can't set window.onload to be a string; you have to point it directly to a function.
I would suggest creating a new function (call it writeColor) that contains if statements based on the value of sessionStorage.colorVar; then you can do window.onload=writeColor;
Alternately, change your window.onload line to window.onload = window[sessionStorage.colorVar + 'Write']; which will grab your function from the global scope and assign it to window.onload.