File extension validation using javascript in MVC

-
This is article which demonstrate the validation of allowed file extension for upload of files in MVC using javascript. In this article i have used validation for valid image format like Jpeg, Jpg,Gif and png image format. If users ties to upload any other file apart from above mentioned file then the javascript function will shows proper message to user to select appropriate files.

 I have used html input file control for uploading of files in MVC application.

 following is the html code for it.


<body>
    <div style="height:50px; padding-bottom:20px;">
      @using (@Html.BeginForm("Create","FileUpload",FormMethod.Post,new{ enctype = "multipart/form-data"}))
{

<input type="file" id="file1" name="sdf" style=" margin-top:0px;" onchange="if( CheckExtention(this.value) ) {parent.ShowHideImage(true);this.form.submit();}" />



}
  
    </div>
</body>

and following is the javascript code to implement the validation


<script type="text/javascript">
  

    function CheckExtention(file)
    {
 var ext=  file.substr(file.lastIndexOf('.'),4).toLowerCase();
 
    if(ext!='.jpg' && ext!='.png' && ext!='.jpeg' && ext!=".gif")
    {
        alert('Only Jpg,png,Jpeg,or gif format allowed');
        
        var file = document.getElementById("file1");
        file.value = "";
        return false;

    }
    else 
    {
        return true;
    }

    }

</script>

I hope all you guys understood the concept.

Kindly let me know if you have any queries

Comments

Post a Comment

Popular posts from this blog

Implement Logging in CSV file using Nlog in .net core MVC application- part 2

-
Image
In previous article " Implement Nlog in .Net core MVC application part 1 "  I have demonstrated how we can implement basic setup of NLog in .core mvc application. In previous article we have logged the exceptions in flat file system. In this article I will show you how you can write the exception and custom logs in csv file. Writing logs in csv file can enable us better readability of logs in tabular form.       Lets start the implementation of it, I going to use the same example project used in previous demonstration. Modify the Nlog.config file as follows, added new target and rule for logging logs in csv file. <?xml version="1.0" encoding="utf-8" ?> <nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd" autoReload="true" throwExceptions="fal
Read more

Implement Nlog in .Net core MVC application part 1

-
Image
Logging is a very important part of the enterprise application/web application. Setting up the logging correctly not only beneficial for long term maintenance of the application but also it is useful tool to find out the RCA in case of mission critical bug arises. Therefor we will going to discuss the various logging technique implementation using Nlog library package. In this article we will going to use .net core application for demonstration but you can implement it in .net framework application also. So lets start the implementation of Nlog in .net core MVC application. Open visual studio 2019/17 and create the new project as shown below.     Select Asp.net core Web App (Model-View-Controller) and provide the project name in project name text box.   Now on next screen click on create button this will create MVC app with .net core Now go to solution explorer and right click on project and click on Manage Nuget Package. Now in Nuget package manager install below listed Nlog packages.
Read more

Angular User Session Timeout example step by step

-
Image
This functionality let the user know that their session is about to expire and that they would be logged out if they didn’t take action. I have written this functionality in Angular for my latest application.  If you are new to Angular 6 then read my article about Setting up Angular 6 step by step before jump to this article to get handy in Angular 6. Dealing with timers in Angular can be significantly different when using React components and subscriptions. The basic premises remains the same, though. We’ll have a service with a timer that will provide a Subject to which consumers of the service can subscribe. A React Subject provides an easy mechanism to trigger a “next” subscription to alert consumers that the timer has expired.   import { Injectable } from '@angular/core'; import { Observable, Subject, Subscription, BehaviorSubject} from 'rxjs/Rx'; @Injectable() export class IdleTimeoutService { private _count: number = 0;
Read more

Restore the lost focus of Auto post back controls in asp.net update Panel control

-
Problem: We put  autopostback controls like textbox, DropDownList controls inside in update panel to reducing the flickering of the Page.but when user uses tab for entering the details  the focus of the control losts. Web site users who prefer to use keyboard need to use mouse to activate appropriate input box or press TAB multiple times. Solution: Step 1: Save following in js file give any name to it (like MyUpdatePanelFocus.js ) var lastFocusedControlId = ""; function focusHandler(e) { document.activeElement = e.originalTarget; } function appInit() { if (typeof (window.addEventListener) !== "undefined") { window.addEventListener("focus", focusHandler, true); } Sys.WebForms.PageRequestManager.getInstance().add_pageLoading(pageLoadingHandler); Sys.WebForms.PageRequestManager.getInstance().add_pageLoaded(pageLoadedHandler); } function pageLoadingHandler(sender, args) { lastFocusedControlId = typeof (document.acti
Read more

Devexpress Datebox date formatting in angular 6 with example

-
The Devexpress DateBox in Angular is a widget that displays the date and time in one of DevExtreme predefined formats or a format defined in an external localization library, or a type in the required date/time value. In this article, the i will provide you different date-format which we can set on DateBox to show date and time to user. Following is the code snippet to add Datebox in your Angular form if the you want to capture only date      <dx-date-box [value]="now" displayFormat="EEEE, MMM dd" type="date" > </dx-date-box> Following is the custom formats we can set and depending upon its converted values will be shown. "dd-MM-yyyy" => 28-10-2018 "EEEE, MMM dd" => Sunday, Oct 28 "dd MMM yyyy EEEE" => 28 Oct 2018 Sunday "dd-MM-yyyy EEEE" => 28-10-2018 Sunday alternatively you can change the format as way you want Following is
Read more