Passing Variable through JavaScript from one html page to another page

Question

I have two pages - "page 1" and "page 2". On page 1 there's an text-box with a value of e.g. 100 and a button at the end.

By pressing the button I want javascript to save the value of the textbox in a global (?) variable and jump to page 2. With "window.onload" I want a second Javascript-function to alert the value saved at page1.

Here's my Javascript code:

<script type="text/javascript">  var price; //declare outside the function = global variable ?  function save_price(){      alert("started_1"); //just for information      price = document.getElementById('the_id_of_the_textbox').value;       alert(price); //just for information          } 

<script type="text/javascript">  function read_price(){      alert("started_2");      alert(price);  } 

On "page 1" I have this send-Button with:

<input class="button_send" id="button_send" type="submit" value="Submit_price" onclick="save_price();"/> 

It starts the Javascript function and redirects me correctly to my page2.

But with this ont the second page:

window.onload=read_price();  

I always get an "undefined" value of the global variable price.

I've read a lot about those global variables. E.g. at this page: Problem with global variable.. But I can't get it working...

Why is this not working?

Answer 1

Without reading your code but just your scenario, I would solve by using localStorage. Here's an example, I'll use prompt() for short.

On page1:

window.onload = function() {    var getInput = prompt("Hey type something here: ");    localStorage.setItem("storageName",getInput); } 

On page2:

window.onload = alert(localStorage.getItem("storageName")); 

You can also use cookies but localStorage allows much more spaces, and they aren't sent back to servers when you request pages.

Answer 2

Your best option here, is to use the Query String to 'send' the value.

how to get query string value using javascript

• So page 1 redirects to page2.html?someValue=ABC
• Page 2 can then read the query string and specifically the key 'someValue'

If this is anything more than a learning exercise you may want to consider the security implications of this though.

Global variables wont help you here as once the page is re-loaded they are destroyed.