JavaScript – How to Use Scriptlet Inside JavaScript

javascriptjsp

Can someone test this example and share the results?
http://timothypowell.net/blog/?p=23
When I do:

var myVar = '<% request.getContextPath(); %>';
alert(myVar);

I get : '<% request.getContextPath(); %>'.

Removing the enclosing single quotes from '<% request.getContextPath(); %>';
gives syntax error.
How can I use the scrptlet or expresion inside a js function?

EDIT: this link has an explanation that helped me:
http://www.codingforums.com/showthread.php?t=172082

Best Answer

That line of code has to be placed in a HTML <script> tag in a .jsp file. This way the JspServlet will process the scriptlets (and other JSP/EL specific expressions).

<script>var myVar = '<%= request.getContextPath() %>';</script>

Note that <%= %> is the right syntax to print a variable, the <% %> doesn't do that.

Or if it is intended to be served in a standalone .js file, then you need to rename it to .jsp and add the following to top of the file (and change the <script src> URL accordingly):

<%@page contentType="text/javascript" %>
...
var myVar = '<%= request.getContextPath() %>';

This way the JspServlet will process it and the browser will be instructed to interpret the JSP response body as JavaScript instead of HTML.

Unrelated to the concrete problem, note that scriptlets are considered poor practice. Use EL.

var myVar = '${pageContext.request.contextPath}';

Related Solutions

java – Using Scriptlet in JavaScript

Yes you can have something like this

function addCombo() {
    var textb = document.getElementById("txtCombo");
    var combo = document.getElementById("combo");

    var option = document.createElement("option");
    <c:forEach var="state" items="${stateList}" varStatus="status">  
    option.text = "${state}";
    option.value = "${state}";
    try {
        combo.add(option, null); //Standard
    }catch(error) {
        combo.add(option); // IE only
    }
    </c:forEach>
    textb.value = "";
}

Also See

Note: I haven't tested this code , this is just a demonstration

JSP – Invoking Java Scriptlet Using HTML

You can use Ajax to submit form to servlet and evaluate java code, but stay on the same window.

<form method="get" action="invokeMe()" id="submit">

       <input type="submit" value="click to submit" />

</form>

<script>
    $(document).ready(function() {
        $("#submit").submit(function(event) {
            $.ajax({
                type : "POST",
                url : "your servlet here(for example: DeleteUser)",
                data : "id=" + id,
                success : function() {
                    alert("message");
                }
            });
            $('#submit').submit(); // if you want to submit form
        });
    });
</script>

Best Answer

Related Solutions

java – Using Scriptlet in JavaScript

JSP – Invoking Java Scriptlet Using HTML

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