How to display the word count while giving text in the ckeditor only

I need to display the word count while giving the text in ck editor only, but with my above code i am able to get the word count on button click.How to display the word count directly while giving text in ck editor instead of button click.

<div>
<ckeditor:ckeditorcontrol id="CKEditor1" basepath="/ckeditor/" runat="server"></ckeditor:ckeditorcontrol>
<asp:button id="btn1" runat="server" onclick="btn1_Click" text="get word count" />
<asp:label id="lbl1" runat="server"></asp:label>
</div>

protected void Page_Load(object sender, EventArgs e)
{
}

protected void btn1_Click(object sender, EventArgs e)
{
string whole_text = CKEditor1.Text;
string trimmed_text = whole_text.Trim();

// new line split here
string[] lines = trimmed_text.Split(Environment.NewLine.ToCharArray());

// don't need this here now...
//string[] split_text = trimmed_text.Split(' ');

int space_count = 0;
string new_text = "";
foreach (string line in lines)
{
// Modify the inner foreach to do the split on ' ' here
// instead of split_text
foreach (string av in line.Split(' '))
{
if (av == "")
{
space_count++;
}
else
{
new_text = new_text + av + ",";
}
}
}

new_text = new_text.TrimEnd(',');

// use lines here instead of split_text
lines = new_text.Split(',');
//MessageBox.Show(lines.Length.ToString());
lbl1.Text = lines.Length.ToString();
}