纯js将form表单的数据封装成json 以便于ajax发送

function form2Json(formName){
var form=document.getElementById(formName);
var sb=new StringBuilder();var rcs=new Map();
for ( var i = 0; i < form.elements.length; i++){
var element = form.elements[i]; var name = element.name;
if (typeof (name) === "undefined" || (name === null) || (name.length === 0)){continue;}
var tagName = element.tagName;
if(tagName ==='INPUT'||tagName === 'TEXTAREA'){var type = element.type;
if ((type === 'text')||(type === 'password') || (type === 'hidden') || (tagName === 'TEXTAREA')){
sb.append("\""+name+"\":\""+encodeURIComponent(element.value.replace(/\r\n/ig,""))+"\"");
}else if((type === 'checkbox') || (type === 'radio')){
rcs.putOverride(name,type);
}else{continue;}
}else if (tagName === 'SELECT'){var oc = element.options.length;
for ( var j = 0; j <oc; j++){
if (element.options[j].selected){sb.append("\""+name+"\":\""+(element.value)+"\"");}
}
}
}
if(rcs.size()>0){
for(var i=0;i<rcs.size();i++){
var r=rcs.element(i);var radio="";
var d=document.getElementsByName(r.key);
if(r.value==="radio"){
for(j=0;j<d.length;j++){
if(d[j].checked){radio=d[j].value;}
}
}else{
for(j=0;j<d.length;j++){
if(d[j].checked){radio+=","+d[j].value;}
}
radio.substr(1);
}
sb.append("\""+r.key+"\":\""+radio+"\"");
}
}
return "{"+sb.toJsonString()+"}";
}function StringBuilder(){
this._element_ = new Array();
this.append = function(item) {
this._element_.push(item);
}
this.toString = function() {
return this._element_.join("");
}
this.toJsonString = function() {
return this._element_.join(",");
}
this.join = function(separator) {
return this._element_.join(separator);
}
this.length = function() {
return this._element_.length;
}
}
function Map() {
this.elements = new Array();
// 获取MAP元素个数
this.size = function() {
return this.elements.length;
}
// 判断MAP是否为空
this.isEmpty = function() {
return (this.elements.length < 1);
}
// 删除MAP所有元素
this.clear = function() {
this.elements = new Array();
}
// 向MAP中增加元素（key, value)
this.put = function(_key, _value) {
this.elements.push({key : _key,value : _value});
}
//增加元素并覆盖
this.putOverride = function(_key,_value){
this.remove(_key);
this.put(_key,_value);
}
// 删除指定KEY的元素，成功返回True，失败返回False
this.remove = function(_key) {
var bln = false;
try {
for (i = 0; i < this.elements.length; i++) {
if (this.elements[i].key == _key) {
this.elements.splice(i, 1);
return true;
}
}
} catch (e) {
bln = false;
}
return bln;
} // 获取指定KEY的元素值VALUE，失败返回NULL
this.get = function(_key) {
try {
for (i = 0; i < this.elements.length; i++) {
if (this.elements[i].key == _key) {
return this.elements[i].value;
}
}
} catch (e) {
return null;
}
}
// 获取指定索引的元素（使用element.key，element.value获取KEY和VALUE），失败返回NULL
this.element = function(_index) {
if (_index < 0 || _index >= this.elements.length) {
return null;
}
return this.elements[_index];
}
// 判断MAP中是否含有指定KEY的元素
this.containsKey = function(_key) {
var bln = false;
try {
for (i = 0; i < this.elements.length; i++) {
if (this.elements[i].key == _key) {
bln = true;
}
}
} catch (e) {
bln = false;
}
return bln;
}
// 判断MAP中是否含有指定VALUE的元素
this.containsValue = function(_value) {
var bln = false;
try {
for (i = 0; i < this.elements.length; i++) {
if (this.elements[i].value == _value) {
bln = true;
}
}
} catch (e) {
bln = false;
}
return bln;
}
// 获取MAP中所有VALUE的数组（ARRAY）
this.values = function() {
var arr = new Array();
for (i = 0; i < this.elements.length; i++) {
arr.push(this.elements[i].value);
}
return arr;
}
// 获取MAP中所有KEY的数组（ARRAY）
this.keys = function() {
var arr = new Array();
for (i = 0; i < this.elements.length; i++) {
arr.push(this.elements[i].key);
}
return arr;
}
}