Javascript validation for empty textbox on button click in asp.net

Question

I have asp.net application with one panel. Inside that panel i have one image button and textbox. I have written a javascript validation function for textbox which will display alert box for entering some values in textbox. Now this function is not working gave run-time error:

Object required

My code is here:

<asp:Panel ID="pnlTop" runat="server">
   <tr height="35px" valign="top">
      <td align="right" valign="middle" colspan="2" height="50">
         <asp:ImageButton ID="imgbtnGOTO" runat="server" ToolTip="View Specific Record" BorderWidth="0"
                                ImageAlign="AbsMiddle" OnClientClick="javascript:return fnCheck()"></asp:ImageButton>&nbsp;&nbsp;
         <asp:TextBox ID="txtPagingGoto" CssClass="clsTableCellLeft" Width="215px" runat="server" CausesValidation="true"></asp:TextBox>
      </td>
   </tr>
</asp:Panel>

My Javascript function is:

function fnCheck() {
    if ((document.getElementById("txtPagingGoto").value).length == 0) {
        alert("The textbox should not be empty");
    }
}

Please suggest solution for this.

Just modify OnClientClick="fnCheck" in ImageButton

user2660112
– user2660112

2013-10-08 10:50:16 +00:00
Commented Oct 8, 2013 at 10:50 — user2660112
– user2660112, Commented Oct 8, 2013 at 10:50

osyan · Accepted Answer · 2013-12-28 15:15:31Z

3

function fncheck()
{
        var pgng = document.getElementById("<%=txtPagingGoto.ClientID%>").value.trim();
        if(pgnd == "")
        {
            alert('The textbox should not be empty...');
            document.getElementById("<%=txtfname.ClientID%>").focus();
            return false;
        }
}

edited Dec 28, 2013 at 15:15

osyan

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answered Oct 8, 2013 at 10:49

The Hungry Dictator

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Comments

Royi Namir · Accepted Answer · 2013-10-08 10:43:16Z

3

Try this :

  function fnCheck() {
         if ((document.getElementById("<%=txtPagingGoto.ClientID%>").value).length == 0) {
             alert("The textbox should not be empty");
    }
}

document.getElementById gets the runtime generated ID which is different(not always) from server side ID.

One way is to use the yellow code as I did.

Also : consider please to use the TRIM method. ( if you need to handle it).

answered Oct 8, 2013 at 10:43

Royi Namir

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Comments

VladL · Accepted Answer · 2014-05-11 07:58:07Z

0

<html>
  <head>
    <script type="text/javascript">
     function validate()
        {
         if(document.getElementById("aa").value=="")
               {
                 alert("this textbox should not be empty");
               }
        }
    </script>
   </head>
  <body>
 <input type="txt" id="aa"/>

  <input type="button" value="submit" onclick="validate()"/>`

  </body>
</html>

edited May 11, 2014 at 7:58

VladL

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answered May 11, 2014 at 7:38

vivek

1

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