Question: I want to use a java script code to insert a desired word in a `TextBox` when an `ImageButton` is clicked. The `TextBox` may have some texts before inserting the desired word. I used the below VB.NET code and it works fine but I want to do it in the client seide. How is it possible? (I am new with java script)

```
  Protected Sub ImageButton1_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles ImageButton1.Click
    Dim emoticsign As String = TextBox2.Text & ":)"
    ScriptManager.RegisterStartupScript(Me.Page, Me.Page.[GetType](), "myScript", "document.getElementById('" + TextBox2.ClientID & "').value = ' " & emoticsign & "';", True)
    SetFocus(TextBox2)
End Sub

```

Answer: 
Just target the element by the id and set the value.

Javascript 

```
 function insertText() {
     document.getElementById("Hello").value = "This is inserted";
 }

```

.aspx

```
<asp:TextBox runat="server" ID="Hello"></asp:TextBox>
<asp:ImageButton runat="server" Text="Insert" OnClientClick="insertText()" />

```

If you are wanting to handle text already being in this textbox and just append to it then you could add an `if/else`, so something like:

```
 function insertText() {
    var textbox = document.getElementById("Hello")
    if(textbox.value != "") {
        textbox.value = textbox.value + " text appended";
        textbox.focus();
    }
    else {
        textbox.value = "This is inserted";
        textbox.focus();
    }

 }

```
[Set Value of Input Using Javascript Function](https://stackoverflow.com/questions/5700471/set-value-of-input-using-javascript-function)

```
// this can all be in one line, but expanded for clarity
var appendValue = 'appended text in here';
var inputElement = document.getElementById('input_element_id');
var updatedInputValue = inputElement.value + ' ' + appendValue;
inputElement .value = updatedInputValue;

```