Question

I got a form, and I want to send hidden input by javascript, how to do it?
F.ex:

<input id="total" type="hidden" value="" name="total" />

And when someone click submit I want to set it value

Answer 1

Are you trying to instantaneously change the value of the hidden input? Something like that can be achieved with the onsubmit event, of course.

var submit = document.getElementById("submit");
var hidden = document.getElementById("hidden");

var eventListener = function(el, type, listener) {
    if(el.addEventListener) {
        el.addEventListener(type, listener, false);
    } else if(el.attatchEvent) {
        el.attatchEvent("on"+type, listener);
    } else {
        el['on'+type] = listener;
    }
};

var onsubmit = function() {
    var newVal = "value to set for hidden input";

    hidden.value = newVal;
};

eventListener(submit, "submit", onsubmit);

The above code will listen to the submit event on the submit button and when triggered, it will change the value of the hidden input. To go into further detail with any answer, we’d need a more descriptive question. Otherwise, I really don’t know what you want.