Develop Reference

Getting JavaScript Error in master page using ASP.NET WEB Form

Java Script not working in Content page using ASP.NET C# and I am trying to count the character of multi-line text box below is character count code.
Getting Below error.
Failed to load resource: the server responded with a status of 404
(Not Found) Uncaught ReferenceError: txtComments is not defined(…)
Below is my code JS and Design code.
<script type="text/javascript">
function characterCounter(controlId, countControlId, maxCharlimit) {
if (controlId.value.length > maxCharlimit)
controlId.value = controlId.value.substring(0, maxCharlimit);
else countControlId.value = maxCharlimit - controlId.value.length;
}
</script>
<fieldset style="width: 280px;">
<legend>Counting Remaining Characters example</legend>
<asp:TextBox ID="txtComments" Width="280px" Rows="4" Columns="12" runat="server"
TextMode="MultiLine" onkeyup="characterCounter(txtComments, this.form.remCount, 150);"
onkeydown="characterCounter(txtComments, this.form.remCount, 150);" /><input type="text"
name="remCount" size="3" maxlength="3" value="150" readonly="readonly" />
characters left
</fieldset>
When I am trying to type some thing values is not changing.

You need to pass this instead of txtComments
<asp:TextBox ID="txtComments" Width="280px" Rows="4" Columns="12" runat="server"
TextMode="MultiLine" onkeyup="characterCounter(this, this.form.remCount, 150);"
onkeydown="characterCounter(this, this.form.remCount, 150);" />

I suggest you to use this instead for the textbox ID, because the id will changed with respect to the page name(as well as the master page name if any) since it is a server side control. Which means the calling method will looks like this :
onkeydown="characterCounter(this, this.form.remCount, 150);"
Additional note: Since you are accessing the value of the Textbox from the javascript method, you need not to pass the ID of the textbox instead of that you can pass it as TextBox. so the passing parameter would be this not this.Id. and have to say thanks to Leopard for pointing this;

How do I add my own attribute to a Telerik RadMaskedTextBox

I need to add my own attribute to a RadMaskedTextBox but can't seem to do it. Any ideas?
Here's the aspx:
<telerik:RadMaskedTextBox
ID="txtSocial_Security_Number" runat="server" SelectionOnFocus="SelectAll" Mask="###-##-####"
requiredrule='<%#required("Social_Security_Number_Or_Federal_Identification_Number")%>'
onkeyup="ValidateTBNew()">
</telerik:RadMaskedTextBox>
The requiredrule pulls a rule from the back end, as you can see. But when Telerik renders the control, the requiredrule is gone! Here's the rendered HTML:
<span id="RadPanelBar1_i2_i0_txtSocial_Security_Number_wrapper"
class="riSingle RadInput RadInput_Default"
style="width:130px;">
<input id="RadPanelBar1_i2_i0_txtSocial_Security_Number"
name="RadPanelBar1$i2$i0$txtSocial_Security_Number"
type="text" size="20"
class="riTextBox riEnabled"
onkeyup="ValidateTBNew()"
value="111-11-1111" />
<input id="RadPanelBar1_i2_i0_txtSocial_Security_Number_ClientState"
name="RadPanelBar1_i2_i0_txtSocial_Security_Number_ClientState"
type="hidden" />
</span>
My onkeyup is there but no sign of the requiredrule. The reason for the requiredrule is so that it can be used to determine one of several states of failure - in the javascript function called in the onkeyup event.

Here's the way I was able to git-er-done...
I was using the RadMaskedTextBox but Telerik says that they are deprecating it. Instead, I used an asp:TextBox and the RadInputManager. Here's the code if you need it.
<asp:TextBox ID="txtSSN" runat="server"
requiredrule='<%#required("Social_Security_Number_Or_Federal_Identification_Number")%>'
onkeyup="ValidateTBNew()"></asp:TextBox>
and
<telerik:RadInputManager ID="RadInputManager1" runat="server">
<telerik:MaskedTextBoxSetting Mask="###-##-####" SelectionOnFocus="SelectAll">
<TargetControls>
<telerik:TargetInput ControlID="txtSSN" />
</TargetControls>
</telerik:MaskedTextBoxSetting>
</telerik:RadInputManager>
This way, the TextBox correctly renders with my extra requiredrule attribute and the formatting of the SSN is done with the RadInputManager.

Getting a AJAX CalendarExtender value from a textbox using javascript

I would like to know how to read the value from the TextBox and assign to another TextBox on button click. This TextBox is attached to the AJAX CalendarExtender. So far I have this. I need this on ShowDate() function in Javascript.
<asp:TextBox ID="txtStartDate" runat="server" ReadOnly="false" Height="28px" Width="283px"></asp:TextBox>
<asp:CalendarExtender ID="ClendarExtender" BehaviorID="CE1" TargetControlID="txtStartDate" runat="server">
</asp:CalendarExtender>
<br />
<asp:TextBox ID="txtShowMessage" runat="server" Height="76px"
style="margin-left: 336px" Width="306px"></asp:TextBox>
<br />
<br />
<asp:Button ID="btnCreateNote" runat="server" OnClientClick="showDate()" style="margin-left: 456px"
Text="Button" onclick="btnCreateNote_Click" />
<br />
then my js is
function showDate() {
var txtDate = document.getElementById('<%=txtStartDate.ClientID %>');
document.getElementById("txtShowMessage").value = txtDate;
}
Dont know what's wrong and no value is there in the textDate.

Try to change your Javascript showDate() method like
<script type="text/javascript" >
function showDate() {
var txtDate = document.getElementById('txtStartDate').value;
document.getElementById('txtShowMessage').value = txtDate;
}
</script>
I checked this function and it works fine, Hope it works for you.

This is because when you write runat="server" then ASP engine prepends some string from its side.
ASP.NET has a built in mechanism (INamingContainer) to ensure than you don't have multiple controls named the same. It does this by adding container prefixes.
So
<asp:TextBox ID="txtShowMessage" runat="server"></asp:TextBox>
will change to something like
<input type="text" id="ctl00_ctl00_txtShowMessage" runat="server" />
So just document.getElementById('txtShowMessage') won't work. You need to get the complete ID. So you can use document.queryselector('[id$=txtShowMessage]'). This means get the element whose ID is ending with txtShowMessage.
Otherwise you can do like this
document.getElementById('<%=txtShowMessage.ClientID %>');
Note
1. The second approach I mentioned is better (Using the ClientID).
2. If you want to know the complete ID, then go to the webpage and view it's source, locate that TextField and check the ID (It won't change everytime, thats fixed)
3. For more information Refer here

How Do I Pass ASP.NET Control Name to Javascript Function?

I have Googled this to death and found lots of 'answers', but none of them will work for me, so maybe you clever people could give me a 'definitive' answer?
I have a Javascript function:
function enableSaveLink() {
document.getElementById('<%= btnSaveLink.ClientID %>').removeAttribute('disabled');
}
This works fine, but obviously it is hard-coded to enable a particular control on my page. What I'd like is to be able to call this function from any control on the page, passing the name of the control I'd like to enable as a variable. So, in an ideal world, my Javascript function would look like this:
function enableControl(ctl) {
document.getElementById(ctl).removeAttribute('disabled');
}
And I'd call it like this:
<asp:button id="btnTestButton" runat="server" Text="Click Me" onclientclick="enableControl('txtTestTextbox') />
<asp:button id="txtTestTextbox" runat="server" enabled="false />
I know the way I've passed the control name would never work, but I've tried passing it in all different ways and none work, so this is just for the purposes of illustration. Can anyone tell me how to actually make this work?

You need to use the ClientID property of the control.
This will help:
<asp:button id="btnTest" runat="server" Text="Click Me"
onclientclick="enableControl('<%= lblTest.ClientID %>') />

Use the this reference (more info here):
<asp:button id="btnTest" runat="server" Text="Click Me" onclientclick="enableControl(this);" />
Then in your script:
function enableSaveLink(elem) {
elem.removeAttribute('disabled');
}
Here you are passing a reference to the object calling the function to the function, you can then just set the attribute on the element rather than finding it in the DOM.
EDIT - Just realised what your intended usage is. If you're looking to fire an event from a disabled element when clicked, then you can't do this from the element. It would need to be handled from some other enabled element. The above method works fine if you intend to disable the element when clicked - but not enable the element when clicked.
EDIT - Just to accompany my comment, if you have a uniform structure like this (i.e. where all inputs have a corresponding label - or even button) then:
<div>
<label onclick="activateSibling(this);">Input One:</label>
<input type="text" />
</div>
You could try this:
function activateSibling(label) {
label.nextSibling.removeAttribute("disabled");
}
I've made a jsFiddle demonstrating my concept in jQuery which seems to work fine.
EDIT - OK, last idea. What about custom attributes. You could add a target attribute to your clickable element which contains the Id you're going to enable, like so:
<label target="active_me" onclick="activate(this);">Click to activate</label>
<input type="text" id="active_me" disabled="disabled" />
And your script:
function activate(label) {
var inputId = this.getAttribute("target");
var input = document.getElementById(inputId);
input.removeAttribute("disabled");
}
Although, it's starting to feel like we're fighting against the technology a little and we're not too far removed from ctrlInput.ClientID. But I suppose this makes your markup a little cleaner and gives you a function that's bindable en masse.

Ok, I've cracked it. There are probably more ways than one to do this, but this is fairly elegant.
My Javascript function:
function enableControl(ctl) {
document.getElementById(ctl).removeAttribute('disabled');
}
My ASP.NET markup:
<asp:Button ID="btnTestButton" runat="server" Text="Click to enable" OnClientClick="enableControl('txtTestTextbox');" />
<asp:TextBox ID="txtTestTextBox" runat="server" enabled="false" ClientIDMode="Static" />
The key is the ClientIDMode property, which, when set to static, means that the control's client-side ID when it is rendered will match the ID you give it in markup. If it's within a naming container you may need to include that in the variable passed in the function call. See here for more info about ClientIDMode.
Anyway, this works for me! Thanks for your input, everyone.

ClientID is used for getting server side control on javascript.
var element=document.getElementById('<%=lblTest.ClientID%>');

Add custom information to text fields to use with javascript

I´m making a google instant-type of remote suggestion script with ajax on a site I'm making.
now I have this:
<input type="text" name="spanishtitle" onkeyup="suggest(this, 'title_es');" onblur="fill();" />
and I would like to move that onkeyup script to a jquery call, so I added this
$('.suggestable').live('keyup', ( function() { suggest(this); } ));
and changed the above to this
<input class="suggestable" type="text" name="spanishtitle" onblur="fill();" />
but I'm missing the 'title_es' parameter which tells the ajax handler what am I looking for.
So what I want to know, basically, is if there's a way to add this parameter to the object, so I can access it from suggest() somehow.

You can add it to your HTML...
<input type="text" name="spanishtitle" onblur="fill();" data-title="title_es" />
And then access it in jQuery...
$('.suggestable').live('keyup',
function() { suggest(this, $(this).attr('data-title')); }
);
The data- prefixed attributes are in the HTML5 spec, and are going to be very useful.
At last, no further excuses for using inline event attributes :)

Assign it as the id of the element and then
$('.suggestable').live('keyup', function() {
suggest(this, $(this).attr("id"));
});
The data-* attribute is html5 as far as I know

You can add it as an attribute to the input, something like:
<input data-lookfor='title_es' class="suggestable" type="text" name="spanishtitle" onblur="fill();" />
then you can access it in jQuery with .attr()
var look_for = $(this).attr('data-lookfor');