setting action of form with javascript wont work

Im trying to set the action of a form with javascript!

How come it wont work on this code: (what happens is that the page gets submitted to itself, as in 'action="#"'

    function validateForm() {
    var nr_of_pics=document.getElementById("annonsera_nr_pics").value;
    var name = document.getElementById("annonsera_name");
    var tel = document.getElementById("annonsera_tel");
    var email = document.getElementById("annonsera_email");
    var area = document.getElementById("annonsera_area");
    var community = document.getElementById("annonsera_area_community");
    var category = document.getElementById("annonsera_category");
    var subcats = document.getElementById("annonsera_subcats").getElementsByTagName("select");
    var headline = document.getElementById("annonsera_headline");
    var description = document.getElementById("annonsera_des");
    var price = document.getElementById("annonsera_price");
    if (nameValid(name) && telValid(tel) && emailValid(email) && areaValid(area) && communityValid(community) && categoryValid(category) && subcatsValid(subcats) && headlineValid(headline) && descriptionValid(descripti开发者_如何转开发on) && priceValid(price)){
        var form = document.getElementById("annonsera").action;
        form = "bincgi/verify_"+category+".php";
        alert (form);
        return true;
        } 
    return false;
}

and the form:

<form name="annonsera" id="annonsera" method="post" enctype="multipart/form-data" onSubmit="return validateForm();">

BY the way, the alert box wont show up either! ALSO, setting the form action manually in HTML works fine, and the form is validated properly!

var form = document.getElementById("annonsera").action;
form = "bincgi/verify_"+category+".php";

These lines aren't doing what you seem the think they're doing.

The first line is creating a variable called 'form', and copying the form's current action into that variable as a string. The second line then sets the variable to a new value, but the form's action isn't being changed because the variable only contained a copy of the form's action.

This would be what you're after:

var formElement = document.getElementById("annonsera");
formElement.action = "bincgi/verify_"+category+".php";

However, I don't know why your alert box isn't showing up at all. Are you certain that all the validity methods are actually being passed?

Try this:

document.getElementById("annonsera").action = "bincgi/verify_"+category+".php";

The problem with your code is that you first read the action attribute into a variable:

var form = document.getElementById("annonsera").action;

and then you set the form variable to a new string but this won't update the value of the DOM element.

Give it simple like

document.annonsera.action = "bincgi/verify_"+category+".php"

and to Submit the form

document.annonsera.submit()