How would I call showItems() function in aspx page from code behind.
<script>
function getItems(){
var items = [];
return items; //items=['a','b','c']
}
<form id="form1" runat="server">
<asp:Hiddenfield id="HiddenField1" runat="server"></asp:hiddenfield>
</form>
code behind:
ScriptManager.RegisterStartupScript(this, GetType(), "items", "<script type='text/javascript'>getItems()</script>", false);
A few things here...
First, you don't "call a client-side function from server-side code." What you can do is include some client-side code which itself will call the function, client-side. Which appears to be what you're doing, but I just want to make sure you understand the difference.
Second, your function is called showItems, but you're calling a function called getItems:
<script type='text/javascript'>getItems()</script>
Call showItems() instead? Like this?:
ScriptManager.RegisterStartupScript(this, GetType(), "items", "<script type='text/javascript'>showItems()</script>", false);
Third, the showItems function returns something. But you're not actually doing anything with that result. You're simply invoking the function and ignoring the result. So it's not really clear what you're trying to accomplish.
var items = showItems(); Then in any JavaScript code for which items is in scope you can use that variable. It works very similarly to C# or, well, just about any other language. When a function returns a value, you store that value in a variable when calling the function.Like this:
Page.ClientScript.RegisterStartupScript(GetType(), "key", "showItems();", true);
Edit: To get the javascript return value at C# code behind Assign the values to the hidden control using the javascript code. Then you can access the Hidden control value in C# code. Take a look at this article. for example:
<script type="text/javascript">
function showItems() {
var items = new Array(3);
items[0] = "name1";
items[1] = "name2";
items[2] = "name3";
items[3] = "name4";
document.getElementById('<%=HiddenField1.ClientID%>').value = items.join(',');
}
</script>
And in the code behind:
string[] itemArr = HiddenField1.Value.Split(",".ToCharArray());
