JavaScript assistance with alert or error message

Expand Post »

I have just written a JavaScript file which calculates a taxi fare based on a starting zone, an ending zone, and the length of the taxi ride. The program appears to work fine, however, I would like to be able to display some type of alert or error message though if the proper input is not typed into the prompts. For example, there are only 3 zones available in my program, zones 1,2 and 3. If someone enters a 4 in the user prompt for the zone, I would like to be able to have a message appear indicating that zone 4 is not a valid zone. OR the alert of error message can even come up after the prompts when my HTML page loads completely stating an invalid character has been entered, please refresh the page and try again or something along those lines. If anyone has any suggestions or advice it would be greatly appreciated. I don't even need for anyone to give me the exact code, but just a direction to go into so I can figure it out. Thanks in advance and have a great day.

jobojo

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

28 posts
since Oct 2008

Permalink

Oct 14th, 2008

Re: JavaScript assistance with alert or error message

Your problem description is quite specific - but ultimately what you are talking about is some type of form validation.

Generally form validation falls into two categories:

1. things you can validate purely on the client - because you don't need access to data or logic on the server side,

and

2. things you can only validate on the server - by accessing server data and/or logic.

I don't know which yours falls into. If you have all the information on the page - then you can easily use Javascript for #1. If your problem falls into "requiring server data" - then you can still use JavaScript - but you will need to make an AJAX call... or otherwise you will have to do the validation on the server. Many server side frameworks include form validation as a built i concept in the framework. (such as Struts)

kburb23

Reputation Points: 10

Solved Threads: 2

Newbie Poster

Offline

10 posts
since Sep 2008

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in JavaScript / DHTML / AJAX Forum Timeline: What is the difference between VB script and Java script?

Next Thread in JavaScript / DHTML / AJAX Forum Timeline: ajax mysql based dopdown

DaniWeb Message

Cancel Changes

User Name
Password