Form validation is the process of checking that a form has been filled in correctly before it is processed.For example, if your form has a box for the user to type their email address, you might want your form handler to check that they've filled in their address before you deal with the rest of the form.So if you select the second item in the drop down, a text field associated with that selection appears.My issue is how to make that text field required, but only required based on drop down selection. I am writing a script that validates two select menus. I need to check that it is not "empty" and if not they are alpha characters with -, space and ' special characters and with a limit of 30 chars. @eyefly: I'm guessing you're using cgiemail to process your form on the server?Again, you might like to open the source code for this form in a separate window, so that you can refer to it as we talk you through.Like our previous example, this page has a form called start at zero (for the first option).
The form is large so I didn't want to paste all here, but the snap shot of the items I'm referring to are: Is it possible to make the the text field with name=googlekey required if some selects Google Search in drop down..not required if they make some other selection? The name of the function is validate Form() for a solution to trapping the space being entered. I get my form to work with the validation, but everyone who first submits the form gets this error: "403 No variable substitutions in template"When you reload the page the form sends perfectly. "\n"), then display the final string in an alert box if valid == false. It has three fields which I want to validate but in testing it the first incident of validation causes the alert to pop up but then when I click OK on the alert it submits the form anyway without letting me complete the field and continue to the other fields.
If the user has not completed more than one field, then they will see an alert box appear for each field that is missing.
Now you know how to write a form validation script that can handle multiple form fields, including text boxes, radio buttons, drop-down lists and check boxes!
Shows you how to write a script that ensures your form is filled in correctly before it's sent to your server.
Great for "required fields" such as email addresses!
Thanks, David[Edited by catron on 16-Feb-11 ] im having trouble with my student registration form.you choose the subjects BSIT, BSMATH, BSED, BEED.year level will be limited until 4 year only while if course is BSCE, BSGE, BSArch it will limit until 5 year.. [code]if ( document.contact_form.contact_name.value == "" ) [code]=space In your example if one enters    it does not trap it. It can be found at; Matt, I find your site very helpful. Validation is working when I test the forms but I am getting emails with 1 or -1 in fields (instead of a valid phone or email, etc.) AND I am getting 20, 40, 80 at one time.