How to assign a java array string to a javascript array string?

Question

Below is my code,

<select name = "department_select">
    <script language = "javascript" type="text/javascript">
        var dept_names = [];
        var index=0,limit,it;
        <% 
        String dept_list[] = dbManager.get_dept_list();
        for(int i=0;i<dept_list.length;i++)
        {
            %>
            dept_names[<%=i%>] = <%=dept_list[i]%>;
            <%
        }
        %>
        limit = dept_list.length;
        for(index=0;index<limit;index++)
        {                       
            document.write("<option>"+dept_names[index]+                                   "</option>");        
        }
    </script>
</select>

I am trying to create a dropdownlist that will access the data from the database and use those data as options of the dropdownlist in the jsp page for a few days now.

When my jsp page is executed it shows the dropdownlist, but there is no option, just blank.

I think assignment at line 10 of the code is not working.

I tried to assign each value of the java array to the javascript array using a loop.

Why this is not working ? I am using oracle database system.

Answer 1

You're missing quotes around the JavaScript strings.

Change

dept_names[<%=i%>] = <%=dept_list[i]%>;

to

dept_names[<%=i%>] = "<%=dept_list[i]%>";

or simply

dept_names.push("<%=dept_list[i]%>");

Change also

limit = dept_list.length;

to

limit = dept_names.length;

Notes :

• there's no reason here to loop twice, once in Java and once in JS. You could do a simple Java loop to build your options
• it would be cleaner and less tedious to use a JSON encoder to directly write your JS literals from Java. This would also avoid errors (like a " in the middle of your string)
• you should declare the variables in JavaScript (limit, index)