Problem:

Internet Explorer can not display the page.

Localhost not able to establish a connection on port..

getting the above messages when trying to run my application locally. I got this problem after installing this week's updates to Vista.  It messed up VS developer server settings. 

Apparently it was due to Definition Update for Windows Defender - KB915597 (Definition 1.53.256.0)

Solution:

Go to c:\Windows\System32\drivers\etc\ and open the file named hosts with a text editor and search for the line containing "::1"  and change "::1" to ":::1" by adding an extra ":" 

It solved the problem on one of my development machine. If it didn’t work, leave a comment.

Update:

Another solution from visual web developer team.

Update:

Same problem is discussed here and here

I have won the 8th Prize in Community-Credit January 2009 contest.It has been an great experience to be a part of the full community and do what I like to do. But to be awarded for doing what you love to do is great.

Microsoft is going to make jQuery part of the official dev platform. JQuery will come with Visual Studio in the long term, and in the short term it'll ship with ASP.Net MVC. It is truly good news for ASP.Net developers

What is jQuery?

jQuery is a lightweight open source JavaScript library.

From jQuery website..

jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.

Blogs posts by Scott Guthrie and Scott Hanselman on this topic.

Here is a way of detecting search engine (Google, live…) crawlers,spiders etc..

Web Site Project is deployed with source code to the server and all compilation takes place at runtime.

Web Application Projects, the code behind classes are compiled to dll. That dll is deployed and at runtime, the compiled code in the dll and the markup is combined to create a class which is used by the server to render output.

Update:

Good post by anthony on this

post by Stephen on this topic

Here is a small code to remove spaces from textbox's text in onblur event.

<asp:TextBox ID="TextBox2" runat="server" onblur="javascript:value=value.replace(/\s/g,'');"></asp:TextBox>

To remove HTML tags..

<asp:textbox id="TextBox2" runat="server" onblur="this.value = this.value.replace(/<\/?[^>]+>/gi, '');">
</asp:textbox>

Please let me know, if you have any issues.

The browser back button cannot be disabled as the browser security will not allow this. If you want user to stay on the same page, even if user presses back button, try this java script..

<script language="JavaScript">

javascript:window.history.forward(1);

</script>

What if the JavaScript is disabled by the client, then this code doesn't work. And also it works great in IE, but not in other browsers. So I do not highly recommend using this.

Here is another solution for back button problem..

Add this code to Page_load

Response.Cache.SetCacheability(HttpCacheability.NoCache);

Response.Cache.SetExpires(DateTime.Now); 

The above code will disable page cache. Since the page is not being cached on the browser, the page will be reloaded when the user hits the back button.

Sometimes we have to capture page close event or navigation event to alert users. For example, Alerting user for navigating away from input page without saving it. Check this java script code..

window.onbeforeunload= function(){
if((window.event.clientX<0) || (window.event.clientY<0))
    {
      event.returnValue = "Are you sure you want to navigate away from this page? You haven't saved this form.";
    }
};

This code works only in Ie6/7. And also keep in mind, we can never catch the browser close event for 100%. For example, what if the user kills the browser process or shut down OS.

I have seen lots of questions in Asp.Net forums for adding/deleting items in drop down list or list box using JavaScript. Here is the code...

<asp:DropDownList ID="DropDownList1" runat="server" Width="182px"> 
<asp:ListItem value="1" Text ="Approve"></asp:ListItem> 
<asp:ListItem value="2" Text ="Accept"></asp:ListItem> 
<asp:ListItem value="3" Text ="Test1"></asp:ListItem> 
<asp:ListItem value="4" Text ="Test2"></asp:ListItem> 
</asp:DropDownList> 

<input type="button" value="Remove selected item" onclick="JavaScript: DeleteItem();" /> 
<input type="text" id="ddlText" name="ddlText" /> 
<input type="text" id="ddlValue" name="ddlValue" /> 
<input type="button" value="Add item" onclick="JavaScript: AddItem();" /> 
<input type="hidden" id="ddlElements" name="ddlElements" runat="server" /> 
<asp:Button ID="Button1" runat="server" Text="Button" />

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

        var dropDownListRef = document.getElementById('<%= DropDownList1.ClientID %>'); 
        var optionsList = ''; 

        if ( dropDownListRef.value.length > 0 ) 
        { 
            var itemIndex = dropDownListRef.selectedIndex;

       if ( itemIndex >= 0 ) 
            dropDownListRef.remove(itemIndex); 
        } 
        else 
        { 
            alert('Please select an item'); 
            dropDownListRef.focus(); 
            dropDownListRef.select(); 
        } 
          

        for (var i=0; i<dropDownListRef.options.length; i++) 
        { 
        var optionText = dropDownListRef.options[i].text;
        var optionValue = dropDownListRef.options[i].value; 
     
        if ( optionsList.length > 0 )
            optionsList += ';'; 
            optionsList += optionText; 
            optionsList += ';'; 
            optionsList += optionValue; 
        } 
        document.getElementById('<%= ddlElements.ClientID %>').value = optionsList; 
    } 


    function AddItem() 
    { 

        var dropDownListRef = document.getElementById('<%= DropDownList1.ClientID %>'); 
        var ddlTextRef = document.getElementById('ddlText'); 
        var ddlValueRef = document.getElementById('ddlValue'); 
        var optionsList = ''; 

        if ( ddlTextRef.value !="" && ddlValueRef.value!="" ) 
        { 
            var option1 = document.createElement("option"); 
            option1.text= ddlValueRef.value; 
            option1.value= ddlTextRef.value ; 
            dropDownListRef.options.add(option1); 
        } 
        else 
            alert('Please enter values'); 
          
        for (var i=0; i<dropDownListRef.options.length; i++) 
        { 

        var optionText = dropDownListRef.options[i].text;
        var optionValue = dropDownListRef.options[i].value; 
          
        if ( optionsList.length > 0 )
        
            optionsList += ';'; 
            optionsList += optionText; 
            optionsList += ';'; 
            optionsList += optionValue; 
        } 
            document.getElementById('<%= ddlElements.ClientID %>').value = optionsList; 
       
    } 

</script>

In Code behind Page_Load, add following code..

if (IsPostBack)
{
    DropDownList1.Items.Clear();
    string[] DropDownListArray = ddlElements.Value.Trim().Split(';'); 
    
    for (int i = 0; i < DropDownListArray.Length; i = i + 2)
    {
        string itemText = DropDownListArray[i];
        string itemValue = DropDownListArray[i + 1]; 

        DropDownList1.Items.Add(new ListItem(itemText, itemValue));
    }

}

string optionsList = string.Empty; 

for (int i = 0; i < DropDownList1.Items.Count; i++)
{
   string optionText = DropDownList1.Items[i].Text;
   string optionValue = DropDownList1.Items[i].Value;
          
    if (optionsList.Length > 0) 
      
    optionsList += ";";
    optionsList += optionText;
    optionsList += ';';
    optionsList += optionValue;
}

ddlElements.Value = optionsList; 

Update:  Client-side changes to a DropDownList/ListBox are not persisted server-side, so any changes made will be lost if a PostBack occurs. Added server-side persistence to code. (Thanks to tip form NC01)