How can I get form data with JavaScript/jQuery?

Question

Is there a simple, one-line way to get the data of a form as it would be if it was to be submitted in the classic HTML-only way?

For example:

Answer 1

You are all not fully correct. You cannot write:

formObj[input.name] = input.value;

Because this way if you have multiselect list - its values will be overwritten with the last one, since it's transmitted as: "param1" : "value1", "param1" : "value2".

So, correct approach is:

if (formData[input.name] === undefined) {
    formData[input.name] = input.value;
}
else {
    var inputFieldArray = $.merge([], $.isArray(formData[input.name]) ? formData[input.name] : [formData[input.name]]);
    $.merge(inputFieldArray, [input.value]);
    formData[input.name] = $.merge([], inputFieldArray);
}