I have an aspx page in which i have 3 asp.net text boxes and 1 asp.net button control.I want to do a client side validation before the post back happens when i click on the button . ie ; If the the page passes the validation check,then only i need to invoke the server side button click event.Can any one help me ? Thanks in advance
Define JS function:
function validate(){
//perform some validation
return $("#myTextbox").val()=="";
}
call it on button control onclick event="return DoValidation();"
If JS function will return false, postback will be canceled.
If you want to integrate with ASP.net validation, need to register your Javascript validator using RegisterValidator declaration.
Don't forget to valiate on the server-side too, as Javascript may be disabled.
Related
I need to disable the submit button, to prevent double posting.
I added the following attributes to the asp:button:
UseSubmitBehaviour="false"
OnClientClick="this.disabled='true';this.value='Please wait ...'"
This works only if on the first click all controls of the form are valid. But if any one of the asp:RequiredFieldValidor fails, the button is disabled until the page is refreshed.
Use the below code:
OnClientClick="if (Page_ClientValidate()) { this.disabled='true';this.value='Please wait ...'}"
Explanation
Page_ClientValidate() This method is used for asp.net client side validation. So, if you page in client side validated then only disable your text box.
i have a textbox on a page, now whenever any age number is entered in that page, that page should be loaded in my datalist, i have created rest of the thing, but i am not getting how to trigger the textbox onkeydown event from asp.net, i know working with that from javascript, but the problem is i have below things done in that function:
it applies the currentpage value to the static variable from textbox
it binds the datalist
it enable disable the next previous buttons accordingly
and i dont think this i can do from javascript, anyone have any resolution, how this could be achieved from server side, onkeydown event
You can capture the keydown event in a javascript function then do a AJAX call to the server. If this does not suit you, then you could try manually do postback in javascript.
So in your textbox:
mytextBox.Attributes.Add("onkeydown", "return doDataListBind()");
Now in the javascript function:
function doDataListBind()
{
__doPostBack("myTextBox"); // etc, etc
// some other code here...
}
More info can be found here:
http://geekswithblogs.net/mnf/archive/2005/11/04/59081.aspx
http://www.asp.net/ajaxlibrary/AjaxControlToolkitSampleSite/
Try looking into or using either:
AJAX Control Toolkit, or
JQuery Autocomplete Plugin
Alternatively you could try to call _postback() function from a client side event/function for your textbox in javascript
How to show javascript alertbox on button click event in asp.net webpage if textbox1.text="" ?
What you must do is attach a script to the button's client click event. In that script, check the value of textbox1. If it's empty, you show the alert and return false to prevent the form from submitting (prevent postback).
To do so, in Page_Load, insert the following:
if (!Page.IsPostBack)
{
string script = string.Format("if (document.getElementById('{0}').value == '') {{ alert('Textbox is empty'); return false; }}", textbox1.ClientID);
btnMyButton.Attributes.Add("onclick", script);
}
Of course, you could encapsulate the script in a reusable method, use jquery to check the value, but this is the big idea.
Are you talking about a server-side button click event? If so, then you can register javascript to run after the page is loaded, but you cannot execute javascript on the server in the context of the browser.
If you meant button click on client side you can use OnClientClick event of the asp.net Button Control. Check the link.
And if you simply want it for Validation purpose only then you can use RequiredFieldValidator and ValidationSummary Controls.
This is probably a simple question.
I use ASP.NET ajax toolkit and Jquery. I want to call a server-side function/method from Javascript and have it update a control. Can i do this?
Client-side
send_request(foobar,args);
Server-side
private void foorbar(){
Label1.Text = "updated";
}
Do you want it to fire a server-side method and update a server-side control on the page? You can create a ASP.NET UpdatePanel, let's say there is a button1 inside, and from your JQuery code, write this.
function OnClick()
{
__doPostBack(button1.ClientID, "argument")
}
and in your server side code, Page_Load event, you will find the EVENTTARGET and EVENTARGUMENT in the REQUEST variable, which contains the information you just postback, you can then update the control in the UpdatePanel itself as long as the control is within the UpdatePanel, it will be handled properly by ASP.NET AJAX.
More details here
http://www.dotnetspider.com/resources/16920-Post-back-gets-demystified-doPostBack-defined.aspx
Yes that can be done Client Callback
You could take a look at ASP.NET Page Methods.
jQuery.ajax({
url:'url to call', //usually webservices in asp.net
dataType:'json',
type:'POST', //(asp.net werbservices by default accepts POST request only)
success:function(data){
//do some thing with this data, like will dom elements etc
}
});
#smkngspcmn:
I placed everything inside an update panel and did something like $('#Year').change(function() { __doPostBack("submit", ""); }); That does do a full post back without Ajax. What am i doing wrong? Should i place the above script inside the update panel as well?
The first argument to __doPostBack() should be the UniqueID of a server-side control inside the UpdatePanel. For example, you can put a hidden button inside the UpdatePanel:
<asp:Button ID="HiddenButton" runat="server"
style="display:none" OnClick="HiddenButton_Click" />
When the button is rendered on the page, you can take the name attribute of the <input type="submit"> element that represents the submit button and use it for the first argument to _doPostBack(). In this way, whenever your script runs it the UpdatePanel will make an asynchronous postback and the HiddenButton_Click event handler will be fired.
I've got a textbox being used to enter a password inside a wizard control. I'm trying to get a password strength meter working with it.
Unfortunately, the password box isn't visible until step 4 and this means that I can't register the event handler onload() and putting some JS next to the PW box to register the event handler doesn't seem to fire. I'm guessing this is due to the contents of the wizard being loaded through an AJAX postback
Can someone please suggest how I can register the event handler? many thanks...
function CheckCustomJSHandlers() {
if (document.getElementById('<%=Password1.ClientID %>')) {
document.getElementById('<%=Password1.ClientID %>').onkeyup = CheckPasswordStrength;
}
}
Add this to your JavaScript:
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(CheckCustomJSHandlers);