Question

I’m newer in JavaScript.So maybe my question will seem naive.

My JavaScript Code:

<script type = "text/javascript">
 var defaultText = "Enter your text here";
 function WaterMark(txt, evt) 
 {
    if(txt.value.length == 0 && evt.type == "blur")
    {
        txt.style.color = "gray";
        txt.value = defaultText;
    }
    if(txt.value == defaultText && evt.type == "focus") 
    {
        txt.style.color = "black";
        txt.value=""; 
    }
 }

ASP declaration:

<asp:TextBox ID="TextBox1" runat="server" Text = "Enter your text here
ForeColor = "Gray" 
onblur = "WaterMark(this, event);" 
onfocus = "WaterMark(this, event);">

My quetstion is about parameters of this two events:

  onblur = "WaterMark(this, event);" 
  onfocus = "WaterMark(this, event);"

If i understood correctly word this means the current control.

And what is meaning of the second parameter, event ?

Thank you in advance!

Answer 1

Those are the event arguments, or EventArgs. They can contain a set of variables that existed at the time the event was created, to provide additional context to the event handler. It’s basically a way to pass information into your event handler.

http://pietschsoft.com/post/2008/11/07/ASPNET-AJAX-Create-a-JavaScript-Component-with-Events.aspx