pass String to function writing javascript

Question

I'm trying to pass a string argument to JavaScript function. for some reason, it can get only ints. I put here only the syntax of the string, since I know that this is the problem because it worls with int.

Code inside sending function:

String counter = "hey";
out.println("<script>parent.update(\'' + counter + '\')</script>");
out.flush();

Eventually I'd expect following update function on my HTML page to be called with value of counter as shown above:

 <script>
      function update(p) { alert(p); }
 </script>

as I mentioned, the javascript file does alert when I send an int, but doesn't react when I send a string.

sorry, my bad, its java. and there are no errors, as i said, it can get an int and do everything easily, but cant work with a string — Zohar Argov, May 31 '16 at 18:40

score 0 · Answer 1 · edited May 23 '17 at 12:15

What you are trying to do called "string interpolation" and used in other languages - you can have formatting string and get values automatically inserted to it.

The code you've used does not do that - since you pass just single string to out.println it is printed as is.

Your options

construct string with concatenation

out.println("<script>parent.update('" +
   counter + 
   "')</script>");

use String.format as shown in String variable interpolation Java

out.println(String.Format("<script>parent.update('%s')</script>",
   counter));

Note: if value you are trying to pass to JavaScript function may contain quotes (especially if coming from user's input) you'd need to escape it first.

pass String to function writing javascript

1 Answers1