세션과 자스의 이해

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:

<input type="hidden" name="pONumb" value="${sessionScope.pONumb} />

or

<div id="product" data-prodnumber="${sessionScope.pONumb}" />

then is JS

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.

<script>

    var pONumb = ${sessionScope.pONumb};

    [...]

</script>

출처 url

https://stackoverflow.com/questions/6918314/using-javascript-can-you-get-the-value-from-a-session-attribute-set-by-servlet-i