如何在javascript中以编程方式提交表单之前检查条件

Question

I have a form which I want to submit only if a condition is true. But there is also a case in which I want to programmatically.

Following works when manually submitting the form:

<input type="submit" value="submit" onclick="return checkForTheCondition();"/>  

Following works for the submitting the form programmatically but it doesn't check for the condition for submitting the form.

$('form').submit();

So I tried to do the following for programmatically checking the condition before submitting the form but when I use the following code it doesn't even submit the form which was being done by $('form').submit(); :

$('form').submit(function() {
    return checkForTheCondition();
});

checkForTheCondition() returns either true or false .

Is it possible to programmatically submit the form just like it works for manual form submission where it checks for a condition before submitting the form?

Answer 1

You should be able to do it this way:

if (checkForTheCondition()) {
    $('form').submit();
}

Edit: I think I understand your problem now.

Calling $('form').submit(function () { ... }); does NOT trigger the event. The function is not a callback! Instead it binds the function to the submit event. So when you call this:

$('form').submit(function() {
    return checkForTheCondition();
});

You do not trigger the event, insted you bind return checkForTheCondition(); this is somewhat the same as onclick="return checkForTheCondition();" but it will be called everytime the form is submitted, and not only when the submit button is clicked.

I would do it this way:

<input type="submit" value="submit">
<script>
    $(document).ready(function () {
        $('form').submit(function() {
            return checkForTheCondition();
        });
    });
</script>

Then you can just call $('form').submit(); and checkForTheCondition() will be called each time. You can read more about jQuery and submit here . Good luck

Edit again:

I realise the easiest solution would be this:

<form method="post" action="somepage" onsubmit="return checkForTheCondition();">
    <!-- Inputs -->
    <input type="submit" value="submit">
</form>

This will make $('form').submit(); and clicks on the submit button call checkForTheCondition() before submitting. Enjoy!

Answer 2

Your code should work if it returns true/false conditionally. You can try this if you want to alert any message on failure of condition.

$(function(){
    $('form').submit(function() {
        if(!checkForTheCondition()){
           //alert message here
           return false;//This will stop the form from being submitted.
        }
        return true;
    });
});

Answer 3

if ($( "#formID" ).submit()){
    alert( "Handler for .submit() called." );     
};

Answer 4

$('#my_form_id').submit(function() {
  var my_value = checkForTheCondition();
  if(my_value == "some returned value"){
    return true;
  } else {
    alert("error in your submission");
    return false;
  }
});