How to call javascript function from asp:textbox?

Question

I am using textbox for searching items from data base and loading them in gridview and

i used custom paging on gridview to show only 25 records per page

and i found java script for searching records on client side as

script>
        function filter2(phrase, _id) {
            var words = phrase.value.toLowerCase().split(" ");
            var table = document.getElementById(_id);
            var ele;
            for (var r = 1; r < table.rows.length; r++) {
                ele = table.rows[r].innerHTML.replace(/<[^>]+>/g, "");
                var displayStyle = 'none';
                for (var i = 0; i < words.length; i++) {
                    if (ele.toLowerCase().indexOf(words[i]) >= 0)
                        displayStyle = '';
                    else {
                        displayStyle = 'none';
                        break;
                    }
                }
                table.rows[r].style.display = displayStyle;
            }
        }

    </script>

and calling this as:

<input name="txtTerm" onkeyup="filter2(this, '<%=GridView1.ClientID %>')" placeholder="Search" type="text"/>

this function search record from activated page and obviously searching from whole database will be done on server side and i used asp textbox

but i need onkeyup="filter2(this, '<%=GridView1.ClientID %>')" event in my asp textbox eg

 <asp:TextBox ID="txtSearch" onkeyup="filter2(this, '<%=GridView1.ClientID %>')"  placeholder="Search" runat="server"  AutoPostBack="True" OnTextChanged="txtSearch_TextChanged" />

but asp didn't allow me to do that..

i need your help to achieve this.

thanks in advance.

EDIT:

I need both searching (client side, server side) in single textbox because

client side allow searching from loaded page of gridview and

server side allow searching from database on clicking

Answer 1

You could add the client attribute of rendered input control via code behind:

protected void Page_Load(object sender, EventArgs e)
{

    txtSearch.Attributes.Add("onkeyup", string.Format("filter2(this,'{0}')",GridView1.ClientID)");
}

EDIT:

After the right comment of @Lukas, we should say that the main problem was the use of <%=GridView1.ClientID %> inline expression inside the textbox webcontrol:

<%= %> will write the string directly to the response-stream, which happens after the server control is constructed, so will be rendered as string and not resolved.

For example:

<asp:Label runat="server" ID="label">test</asp:Label>
    <asp:TextBox runat="server" ID="txt" Text="<%# label.ID %>" onkeyup="alert('<%: label.ID %>')"></asp:TextBox>

This is what we have in output: