Question

Here is my question, I am using jsp script, trying to match a key word in requesting url and do something:

    <script>
     $url = '${pageContext.request.requestURL}';

    if("${fn:contains(url, 'key')}" == true){
        ...
    }
....

But this doest work… I am not sure where the problem is but I want it to be like when url contains this string, go in to the if condition.

Thank you

Answer 1

You are mixing JSP/EL and JavaScript as if they run in sync. This is wrong. JSP/EL runs in webserver and produces HTML code which get executed in webbrowser. JavaScript (JS) is part of the generated HTML code and runs in webbrowser only.

You need to do it either fully in JSP/EL, or fully in JavaScript. You can use JSP/EL to dynamically generate JS code which get later executed when the page arrives at browser. Rightclick page in browser, do View Source to see what JSP/EL has generated. You should not see any line of JSP/EL. You should only see HTML/JS code. It’s exactly that JS code which get executed then.

You’re using a JSP EL function to test a JS variable which isn’t in the variable scope at that moment at all. This is not going to work. It can only test JSP/EL variables.

Here’s how you could do it in pure JS:

<script>
    var url = window.location.href;

    if (url.indexOf('key') > -1) {
       // ...
    }
</script>

If you really insist in doing it using JSP/EL, you could do as follows:

<script>
    var url = '${pageContext.request.requestURI}';

    if (${fn:contains(pageContext.request.requestURI, 'key')}) {
       // ...
    }
</script>

This will then generate the following JS code (rightclick page in browser and View Source to see it):

<script>
    var url = '/some/uri';

    if (true) {
       // ...
    }
</script>

But this makes no sense. Whatever functional requirement you need to solve, you need to think twice about the right approach. Feel free to ask a new question about solving the concrete functional requirement the proper way.