Javascript calling Java value

Question

Hi,
I've got a slight problem on my JSP page.
I have a value thru a value,
request.getParameter("adcomments");I'm trying to call it via javascript in an input value like the following:
<input name="activate" type="radio" value="3" onClick="document.getElementById('reasondeny').style.display='';document.form1.adm_noapproval.value='"+admconts+"';">I've also set the value in a script tag up the page, referencing the variable as
<script language="javascript">
  var admconts = "";
  admconts += admconts + <%=admcomments%>;
alert(admconts);
  </script>With everything I've tried so far, I've gotten a mixture of unterminated string literal errors and this type of error:
Error: missing ; before statement
Source File: http://10.244.212.97:8080/murach/chngctrl/change_ctrl_admin5b.jsp?primID=3181
Line: 405, Column: 41
Source Code:
admconts += admconts + 1/26 - Submit to Default Audit for gap analysis, due 2/2.  
any ideas on where I'm going wrong? Any feedback would be appreciated. Unfortunately the other posts regarding similar javascript issues weren't able to help me solve this.

Answer 1

Unfortunately the other posts regarding similar javascript issues weren't able to help me solve this.If you've read the other posts, then you've probably seen this answer before.
Java is not Javascript. The two can't communicate or share variables directly.
Java/JSP runs on the server, produces an HTML page, and stops running.
Javascript starts running in your browser when/as the page is loading.
You can not communicate directly between the two.
To run java again, you have to send a new request (submit a form, click a link, make an Ajax call)
What you CAN do in the JSP is produce javascript code onto the html page that will be run when in the browser. So you can create basic javascript variables that get their initial value from java/jsp.
// java code declaring a variable
<%  String adcomments = request.getParameter("adcomments"); %>
<script language="javascript">
<!--
// javascript code declaring a variable.
  var adcomments = "<%= adcomments %>";
//-->
</script>Say that you run this code, and pass a value of "This is my comment" as the parameter.
Java would run, retrieve that parameter, and then generate an HTML page like the following
<script language="javascript">
<!--
// javascript code declaring a variable.
  var adcomments = "This is my comment";
//-->
</script>Thats as close as you can get to java/javascript communication.
Note that it doesn't directly copy the value, just generates the value onto the page. You have to ensure that it is valid javascript.
If your parameter has characters like quotes, newlines etc etc, then that may result in a javascript syntax error. A function to escape javascript characters like that is normally called for. ie replace newlines with \n, and quotes with \"
Hope this helps,
evnafets