Stuck (once again) on Form Validation

Discussion in 'Web Design & Coding' started by madmatt, Dec 19, 2006.

  1. madmatt

    madmatt Bow Down to the King Political User

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    Here's what I would like to do.

    I have a form with the following fields (* = required):

    Contact Name (at least 8 characters) *
    Company Name
    Street Address (at least 8 characters) *
    City (at least 5 characters) *
    State (select box) *
    Zip (5 digits - numbers only) *
    Phone (10 characters) *
    Fax (10 characters)
    Email (check format) *
    Message (at least 8 characters) *

    To Start
    All labels start in black.

    Data Input - Valid Data
    Label remains black if the data is valid.

    Data Input - Invalid Data
    Label changes to red if the data is invalid.

    If they press submit and all the data is valid then the form transmits. If the data is not valid then an alert will appear.

    If anyone knows of a tutorial, a book (available to purchase), or even a tutor/helper (I will pay you for your time) that would guide me in the right direction then please post and let me know.

    Thank you.
     
  2. kcnychief

    kcnychief █▄█ ▀█▄ █ Political User Folding Team

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    Maybe a silly question but what language are you trying to do this in? I would assume .ASP or PHP?
     
  3. madmatt

    madmatt Bow Down to the King Political User

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    PHP, but if it can be done with DHTML/JavaScript then it can be applied towards ASP as well.
     
  4. Khayman

    Khayman I'm sorry Hal... Political User Folding Team

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  5. madmatt

    madmatt Bow Down to the King Political User

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    Yes, but I don't want to use alert boxes. I am currently using those and I dislike them (annoying at best). I want to learn how to change the text color of the label and use "onChange" or something similar.
     
  6. Khayman

    Khayman I'm sorry Hal... Political User Folding Team

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    well the page was mostly meant to show some validation methods, not just to copy wholesale.

    change the event to OnChange (or OnLostFocus)

    instead of sending the alert the its something like document.textboxname.className = "failed";

    className is a css class, with its text box style set to red or whatever
    or set the style property document.textboxname.style.property="background-color: red"

    (the code is just examples, i haven't looked up exact syntax.
    w3schools is a good place to learn
    http://www.w3schools.com/js/
     
  7. madmatt

    madmatt Bow Down to the King Political User

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    Okay, I understand so far.

    How do I change the style property for a <label>?

    I am using <label for="phoneNumber"> ... etc.

    document.???.className='invalid';
     
  8. Geffy

    Geffy Moderator Folding Team

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    I would not recommend changing the label

    I typically have this as a form element

    <input type="text" name="firstname" id="firstname" size="30"/>

    you can then have a javascript on submit which checks the fields, say you have in the validation script a mapping of field ids to validation functions, or maybe a switch case, whatever you choose it doesnt really matter.

    If you find an error you can just do
    document.getElementById('firstname').className = 'invalid'

    If you are using maybe the Prototype javascript library then this can be boiled down to

    $('firstname').className = 'invalid'

    Also you are going to need to have your validation on the server side as well, so it may well be an idea to just write the validation on the server side then use XmlHttpRequest to validate on the client side using your server side code. Means you only need to have your validation code in one place.
     
    madmatt likes this.
  9. GEN3RIC

    GEN3RIC Moderator Folding Team

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    1 vote for ASP.NET 2.0 .. i love me some Visual Studio!
     
  10. Geffy

    Geffy Moderator Folding Team

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    I take it you really like amazingly useless __doPostBack crap that MS decided to use *everywhere*. I wouldn't mind it if it degraded well with Javascript turned off but it doesn't, it just doesnt work at all.
     
  11. GEN3RIC

    GEN3RIC Moderator Folding Team

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    I haven't run into any issues - but I could see where it could cause them..
     
  12. albybum

    albybum Penguin Rancher

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    This is a bit brute force, but see if this helps.

    Code:
     
    <html>
    <head>
    <title>Demo</title>
    <script type="text/javascript">
    function validateForm()
    {
     var e;
     // Validate Contact Name
     e = document.getElementById("txtContactName");
     // if bad length, set error 
     if (e.value.length < 8)
     {
      document.getElementById("lblContactName").style.color="#FF0000";
      document.getElementById("frmContactErrors").innerHTML = "Contact name must contain 8 characters";
      return;  // exit validation on error
     } 
     else // otherwise, clear any old errors
     {
      document.getElementById("lblContactName").style.color="#000000";
      document.getElementById("frmContactErrors").innerHTML = "";
     }
     
     // todo: other textbox validation
       
     // assume if we got this far, there were no errors, so submit
     document.frmContact.submit();
    }
    </script>
    </head>
    <body>
     
    <form name="frmContact" id="frmContact" method="post" action="someurl.php" onsubmit="validateForm();">
    <label id="lblContactName" for="txtContactName">Contact Name</label>
    <input id="txtContactName" name="txtContactName" type="text" value="" onchange="validateForm();" />
    <br />
    <label id="lblCompanyName" for="txtCompanyName">Company Name</label>
    <input id="txtCompanyName" name="txtCompanyName" type="text" value="" onchange="validateForm();" />
    <br />
    <input type="button" value="Submit!" onclick="validateForm();" />
    </form>
    <div id="frmContactErrors"><!-- --></div>
    </body>
    </html>