codetoad.com
  ASP Shopping CartForum & BBS
  - all for $20 from CodeToad Plus!
  
  Home || ASP | ASP.Net | C++/C# | DHTML | HTML | Java | Javascript | Perl | VB | XML || CodeToad Plus! || Forums || RAM 
Search Site:



Home » Javascript » Article

Javascript Form Validate Empty Field function

Article by:  Jeff Anderson  ( 1362 ) (2/26/2002)
Bookmark us now! Add to Favourites
Email a friend!Tell a friend
Summary: This javascript function allows you to check whether a form field has been completed or not.
Viewed: 518864 times Rating (64 votes): 
 3.3 out of 5
 Rate this Article  Read Comments  Post Comments


This function can be used to check whether the user has entered anything in a given field. There are two possibile types of 'emptiness' a form can return - a zero length string, or a null value. Here we simply check both these options, and return true if either of these are found to be true.





function IsEmpty(aTextField) {
   if ((aTextField.value.length==0) ||
   (aTextField.value==null)) {
      return true;
   }
   else { return false; }
}	


To check the particular field, you need to pass it in, in the form document.formname.fieldname

It's important to remember to give your form a name in the <form> tag which is referenced here. So, for example, if your form name is form1, and the field name is 'address1' you call the IsEmpty function as follows :


To understand more about how to use the IsEmpty function to validate a form, see Form Validation function






CodeToad Experts

Can't find the answer?
Our Site experts are answering questions for free in the CodeToad forums
Rate this article:     Poor Excellent
View highlighted Comments
User Comments on 'Javascript Form Validate Empty Field function'
RELATED ARTICLES
Javascript - Enable and Disable form elements
by Jeff Anderson
This is a relatively little known and under-used feature of javascript which can be very useful in guiding a user through a form. Using the disabled tag, you can switch on and off elements in a form.
Check IsNumeric Function
by Jeff Anderson
A javascript validation function to check whether the details entered by a user are numeric.
Javascript Onload Event
by Jeff Anderson
Sometimes you need to perform an action immediatley after the page has loaded. That's when the onLoad Event Handler comes in handy
Javascript Get Selected Text
by Jeff Anderson
A cross-browser script to get text selected by the user
Form Validation Function
by Jeff Anderson
A javascript validation function that you can use to validate all types of forms.
JavaScript Field Is Empty Form Validation
by Jeff Anderson
This javascript function allows you to check whether a form field has been completed or not.
Check Email Validation Function
by Jeff Anderson
A javascript validation function to check whether the user has entered a valid email address in a form.
Javascript onUnload Event Handler
by Jeff Anderson
The onUnload Event Handler allows you to perform an action as the user leaves the page.
Multiple submit buttons on a single form
by Kiran Pai
This script shows you how to submit the contents of a form to different programs depending on which Submit button you press. Additionally it also shows how to call two different functions when you press the Submit button.
Simple date validation
by Chris Hogben
function that takes a date in three parts, day, month and year - returns true if it's a valid date.








Recent Forum Threads
• Global.Mapper.v15.2.3.b060614
• Geometric_Glovius_Pro_v3.6.1
• VERO.SurfCAM.v2014
• Schlumberger.Petrel.V2013.2
• Petrel.V2013.2
• Altair.HyperWorks.v12
• VoluMill.v6.1
• VoluMill.NEXION.6
• VERO.SurfCAM.v2014


Recent Articles
ASP GetTempName
Decode and Encode UTF-8
ASP GetFile
ASP FolderExists
ASP FileExists
ASP OpenTextFile
ASP FilesystemObject
ASP CreateFolder
ASP CreateTextFile
Javascript Get Selected Text


© Copyright codetoad.com 2001-2014