Using Javascript can you get the value from a session attribute set by servlet in the HTML page

Question

I have a servlet that forwards to a HTML page, using redirect. Because I am using ajax and php on the html page to do other functions. Can turn into a jsp. Is there a way I

Answer 1

No, you can't. JavaScript is executed on the client side (browser), while the session data is stored on the server.

However, you can expose session variables for JavaScript in several ways:

• a hidden input field storing the variable as its value and reading it through the DOM API
• an HTML5 data attribute which you can read through the DOM
• storing it as a cookie and accessing it through JavaScript
• injecting it directly in the JS code, if you have it inline

In JSP you'd have something like:

Then in JS:

// you can find a more efficient way to select the input you want
var inputs = document.getElementsByTagName("input"), len = inputs.length, i, pONumb;
for (i = 0; i < len; i++) {
    if (inputs[i].name == "pONumb") {
        pONumb = inputs[i].value;
        break;
    }
}

or:

var product = document.getElementById("product"), pONumb;
pONumb = product.getAttribute("data-prodnumber");

The inline example is the most straightforward, but if you then want to store your JavaScript code as an external resource (the recommended way) it won't be feasible.