CODEWITHSUNDEEP
javascriptjspmethodsparametersget
Aishwarya Shiva
Aishwarya Shiva

Reputation: 3416

Pass a GET parameter to a JavaScript function?

I have this code

<%=out.write("<input 
  type=\"hidden\" 
  id=\"tid\" 
  value=\""+request.getParameter("id").toString()+"
\"/>")%>
<script type="text/javascript">
  getPage(document.getElementById("tid").value)
</script>

This code creates a hidden field with the value came from

<site root>/viewPage.jsp?id=erwdf

url and pass the value of this hidden field to a jsp function. When I ran this code on Tomcat it gave an error as

The method print(boolean) in the type JspWriter is not applicable for the arguments (void)

on JSP code line I given above. So am I doing anything wrong or is there any alternative method to pass a GET parameter to a JavaScript function? I don't know much about Javascript just started to learn it.

Upvotes: 1

Views: 14134

Answers (3)

BalusC
BalusC

Reputation: 1109745

Why so overcomplicated with a hidden field?

Just do

getPage('<%=request.getParameter("id")%>');

Or easier, with EL

getPage('${param.id}');

You may only want to escape special JS characters by Apache Commons Lang StringEscapeUtils, otherwise the generated JS code may break whenever the parameter value contains a single quote or any other special JS character.

getPage('<%=StringEscapeUtils.escapeJavaScript(request.getParameter("id"))%>');

Or when in EL

getPage('${util:escapeJS(param.id)}');

See also:

Upvotes: 3

dldnh
dldnh

Reputation: 8961

I believe you meant <%out.write instead of <%=out.write

about the other issue from the comments, this will assist with getPage and perform escaping of quotes, other special chars...

<script type="text/javascript">
  getPage("<% try {
      out.write(URLEncoder.encode(request.getParameter("id").toString(), "UTF-8"));
    } catch (Exception e) {
    } %>")
</script>

Upvotes: 2

Reinard
Reinard

Reputation: 3654

You don't have to store it in a hidden field to access it from js. You can read it from the documents location. I personally use a method like this to grab GET parameters from my url.

function getUrlVars() {
    var vars = [], hash;
    var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
    for (var i = 0; i < hashes.length; i++) {
        hash = hashes[i].split('=');
        vars.push(hash[0]);
        vars[hash[0]] = hash[1];
    }
    return vars;
}

var id = getUrlVars()['id'];

Upvotes: 2

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