passing parameters from Javascript

Question

I have the typical HTML "contact me" page, i.e. name, e-mail address and message. Since I want to do input validation on the page itself using Javascript, I can't use a "submit" button, otherwise the attached Javascript function would be ignored. At least that's how I understand it, CMIIW.
I tried to load the next page wrting "location = mail.php" but it appears that the form parameters don't get passed to my php page this way.
How do I validate input in Javascript and pass parameters to my php page when ok?
TIA
Steven

Answer 1

Use the onSubmit event. Attach it to your form and if it returns true then your form will be sent to the PHP page. Read more here.

Answer 2

You should still use the submit button to submit the form, that is the correct behavior.

Input validation should be done using the <FORM>'s onSubmit event. It should look something like this:

<script>
    function validate() {
        var isFormValid = whatever; // validate form
        return isFormValid;
    }
</script>

<form action="your.php" method="POST" onSubmit="return validate()">
    <!---fields--->
</form>

Answer 3

You can use a form with an onsubmit handler on it, that returns false if the validation failed. If the check is ok, return true and the form will submit normally.

You'd have a javascript function something like this:

function check_it_all() { 
  if (all_ok) {
     return true;
  } else {
     return false;
  }
}

And the form

<form action=.....  onsubmit="return check_it_all();">
....
</form>

Answer 4

If possible can't you use a JavaScript library like Jquery? It probably would make your life alot easier and they have tons of plug-ins for validation.

Such as

http://bassistance.de/jquery-plugins/jquery-plugin-validation/

Answer 5

the function validate() return a bool.
This will stop the submission if validate() returns false.

<input type="submit" onclick="return validate()" value="click" />

I am an aspx.net developer so I am used to putting the validation call on the button.