表单序列化 Form serialize

序列化：
序列化是将对象状态转换为可保持或传输的格式的过程。与序列化相对的是反序列化，它将流转换为对象。这两个过程结合起来，可以轻松地存储和传输数据。

function serializeForm(whichForm){
    var parts = new Array();
    var field = null;
    for (var i = 0, len = whichForm.elements.length; i < len; i++) {
        field = whichForm.elements[i];
        switch (field.type) {
            case "select-one":
            case "select-multipe":
                for (var j = 0, optLen = field.options.length; j < optLen; j++) {
                    var option = field.options[j];
                    
                    if (option.selected) {
                        var optValue = "";
                        if (option.hasAttribute) {
                            optValue = (option.hasAttribute("value") ? option.value : option.text);
                        }
                        else {
                            optValue = (option.attributes["value"].specified ? option.value : option.text);
                        }
                        parts.push(encodeURIComponent(field.name) + "=" + encodeURIComponent(optValue));
                    }
                }
                break;
            case undefined:
            case "file":
            case "submit":
            case "reset":
            case "button":
                break;
            case "radio":
            case "checkbox":
                if (!field.checked) {
                    break;
                }
            default:
                parts.push(encodeURIComponent(field.name) + "=" + encodeURIComponent(field.value));
        }
    }
    return parts.join("&");
}