How to invoke an event after losing focus from a textbox that was just filled out?

I have two text boxes: A and B using Html.textboxfor. TextBox 'A' is enabled and TextBox 'B' is disabled.

When I type values in Textbox 'A' and change focus away from the textbox, TextBox 'B' should be populated with some value.

For example: I am entering the value of TextBox A = "King"; if the focus is lost from the box, the value in the Textbox B should be "Pe开发者_开发知识库ter", which should be filled automatically.

you can jsut give the textbox an attrbiute of onblur and call a method which will fill the second textbox

something like:

   <script language="javascript">
       function fllB()
       {
          var txtB = document.getElementById("txtB");
          var txtA = document.getElementById("txtA");

          if (txtA.value == "King")
          {
              txtB.value = "Peter";
          }
        }
    </script>

<input type="text" id="txtA" onblur="fillB()" />
<input type="text" id="txtB" />

Below is the javascript function that I wrote to validate my input "Price" currency value.

<script language="javascript">
function validatePrice(textBoxId) {
    var textVal = textBoxId.value;
    var regex = /^(\$|)([1-9]\d{0,2}(\,\d{3})*|([1-9]\d*))(\.\d{2})?$/;
    var passed = textVal.match(regex);
    if (passed == null) {
        alert("Enter price only. For example: 523.36 or $523.36");
        textBoxId.Value = "";
    }
}

If you want to fire the validation after you lost a focus from text box, then use “onblur” event which is as same as OnLostFocus() in most of the WinForm controls.

<asp:TextBox ID="TextBox19" runat="server" Visible="False" Width="183px" 
                onblur="javascript:return validatePrice(this);"></asp:TextBox>

Since you are using ASP.NET, why dont you used the .NET toolbox like asp:textbox. It will be easier to maintain also.

protected void TextBox1_TextChanged(object sender, EventArgs e)
{
    if (TextBox1.Text == "King")
    {
        TextBox2.Text = "Peter";
    }
}

It looks as though you want your second textbox to always be disabled? If so include the disabled property in the textboxfor:

<%: Html.TextBoxFor( x => x.XXX, new { id = "txtA" }) %>    
<%: Html.TextBoxFor( x => x.XXX, new { id = "txtB", disabled="true" }) %>

For the JavaScript, I'm assuming you are using the jquery that is included with mvc: (If you don't want to clear txtb if the value is removed from box A, then remove the else statement)

    $(function() 
{
    $("#txtA").change(function()
    {
        if ($("#txtA").val().length > 0) {

            $("#txtB").val(function()
            {
                // Do something to populate #txtb ex: Peter
                var myVar = "Peter";

                return myVar;
            }); 
        }
        else 
        {
            $("#txtB").val("");
        }
    });
});

jQuery:

<script type="text/javascript">
  $(function()
  {

    $("#txtA").change(function()
    {
      if(this.value == "King") 
        $("#txtB").attr("disabled", "").val( "Peter" );
    });

  });
</script>