Question

Okay, I’ve created an array in c# and want to access the values in a javascript for loop. Here’s my global c# variables:

protected int count;
protected string[] arr = new string[20];

From there I add string values to the array in, let’s say, the Page_Load() event.

And here’s my ideal javascript code:

var count = <%= count %>;
for (var i = 0; i < count; i++) 
{
document.write(<%= arr[i] %>);
}

Now if I were to just use arr[0] that would pop up with the correct information for arr[0], so I know I’ve got that part right, but is there a way to use that javascript variable “i” inside the <%= %> tag?

Answer 1

The ASP.NET parts of the code execute on the server. JavaScript is executed in the browser. The server just sees the JavaScript as text, it is meaningless and non-functional. Only when the browser receives the page and interprets the JS is it executed.

Remember, the server and the client PC are two different systems connected by a network. If you want to process data from system A on system B, you need to send the data to B.

If you want to send the data in the array to the browser so it can use it in some JavaScript, you need to serialize the array.

Something like this:

var myArray = <% = new JavaScriptSerializer().Serialize(serverSideArray) %>;
for(var i = 0; i < myArray.length; i++) {
    document.write(myArray[i]);
}