Passing values to javascript from database

Question

hi friends,
I have to fetch values from the database and pass the values to the java script variable.
I tried this, but is not working. When i place the script inside the java, it isnt working. Iam passing value to this script variable as argument to a function. This is my code:
ResultSetMetaData rsmd = rs.getMetaData();
int numberOfColumns = rsmd.getColumnCount();
while (rs.next())
for (int i = 1; i <= numberOfColumns; i++)
count=count+1;
if (i > 1)
columnValue = rs.getString(i);
%>
<script>
var hcbList = [<%=request.getParameter("columnValue")%>];
</script>     
<%           
System.out.println("");
st.close();
%>
Pls solve the problem. Its very urgent!
thanx

Answer 1

Keep this in mind: JSP is source generation software.
In other words JSP generates the HTML and/or Javascript that will be rendered on the browser. So What you need to do is keep the JSP and Javascript separate in your mental picture. You ask yourself, "what would the finished Javascript code look like that would give me the results?" Then you apply JSP as a template to fill in the blanks. In your example you want a list or an array of values in your Javascript. I don't use Javascript to often but from memory I belive an array in Javascript is something like this:
<script>
var hcbList = {"val1", "val2, "valx"};
</script>That's what the finished Javascript would look like. Now you apply JSP as a template.
<!-- This is the fill-in-the-blank template
<script>
var hcbList = {<%=insertArrayHere%>};
</script>Now you fill in the blanks
//insertArrayHere is your blank
String insertArrayHere = "";
//iterate over the collection and build a string that represents the JS array
for(int i = 1; i <= numberOfColumns; i++)
   //wrap each value with quotes if it is to be a JS string
   insertArrayHere += "\"" + rs.getString(i) + "\"" + ","; //terminate with a comma
//trim the last comma off the array guts
insertArrayHere = insertArrayHere.substring(0, insertArrayHere.length() - 1); Now I'm sure that's not exactly what you want because it looks like you got some crazyness going on in your logic. I don't know how you can query the using values from the database. Anyhow it poses as a good example of how to apply the concept of the two technologies. (Also, why are you doing a System.out from JSP? You should be calling log() if you want console output.) The whole idea is that JSP can NOT talk directly to Javascript. It can only generate Javascript dynamically before it is received by the browser.