js处理json格式的插入、修改、删除，以及字符串的比较等常用操作
demo 1：
json格式的插入、删除
<html>
<head>
<title></title>
<script language="javascript">
function change(){
var obj=document.getElementById("floor");
if (document.getElementById("qu").value=="1"){
var t=document.createElement("OPTION");
t.text="第五楼";
t.value="5";
obj.add(t);
}else if(document.getElementById("qu").value=="2"){
for(var i=0; i<obj.length;i++){
if(obj.options[i].value=="5"){
obj.remove(i);
return;
}
}
}
}
</script>
</head>
<body>
<form id="form1" name="form1" method="post" action="">
<select multiple="multiple" name="qu" id="qu" onchange="change()" style="width: 150px; height: 300px;">
<option value="请选择所在区">--请选择所在区--</option>
<option value="1">南开区</option>
<option value="2">红桥区</option>
</select>
<select multiple="multiple" name="floor" id="floor" style="width: 150px; height: 300px;">
<option value="请选择楼层">--请选择楼层--</option>
<option value="1">第一楼</option>
<option value="2">第二楼</option>
<option value="3">第三楼</option>
<option value="4">第四楼</option>
</select>
</form>
</body>
</html>
运行结果：
demo2：
<!DOCTYPE html>
<html>
<script language="javascript">
function toLeft() {
var list1 = document.getElementById("list1");
var list2 = document.getElementById("list2");
for (var i = list2.options.length-1; i >= 0 ; i--) {
if(list2.options[i].selected ==true){
var op = document.createElement("option");
op.text = list2.options[i].text;
op.value = list2.options[i].value;
list1.add(op);
list2.remove(i);
}
}
}
function toRight() {
var list1 = document.getElementById("list1");
var list2 = document.getElementById("list2");
for (var i = list1.options.length-1; i >= 0 ; i--) {
if(list1.options[i].selected ==true){
var op = document.createElement("option");
op.text = list1.options[i].text;
op.value = list1.options[i].value;
list2.add(op);
list1.remove(i);
}
}
}
function submit() {
var list2 = document.getElementById("list2");
var innerStr = "";
for (var i = 0; i < list2.options.length; i++) {
innerStr += i + " - " + list2.options[i].text + " : " + list2.options[i].value + "</br>";
}
var wt = document.getElementById("wt");
wt.innerHTML = innerStr;
}
</script>
</head>
<body>
<div>
<select multiple="multiple" id="list1" style="width: 500px; height: 100px;>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
<input type="button" value=">" onclick="toRight();submit()"/>
<input type="button" value="<" onclick="toLeft();submit()"/>
<select multiple="multiple" id="list2" style="width: 500px; height: 100px;>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
<input type="button" value="submit" onclick="submit()"/>
<div id="wt"/></div>
</body>
</html>
运行结果：
Demo 3：
json元素的插入、修改、删除，以及与字符串的转化格式
<html>
<head>
<title>IT-Homer demo</title>
</head>
<body>
<input type="button" id="parse" value="parse json" onclick="parseJson()" />
<div id="txt" />
<script type="text/javascript">
function parseJson(){
var txt = document.getElementById("txt");
var jsonData = '{"name":"it-homer","age":25}';
var field = "";
if(jsonData.length <= 0){
jsonData = '{}';
}
var jsonObj = JSON.parse(jsonData); // ok
// var jsonObj = eval('(' + jsonData + ')'); // ok
// var jsonObj = jsonData.parseJSON(); // error
field += "name = " + jsonObj.name;
field += ", age = " + jsonObj.age;
jsonObj["sex"] = "boy"; // add json, {"name":"it-homer","age":25,"sex":"boy"}
// createJson(jsonObj, "sex", "boy");
jsonData = JSON.stringify(jsonObj); // ok
// jsonData = jsonObj.toJSONString(); // error
var sex = "";
if(jsonObj.length > 0) {
sex = jsonObj.sex;
}
txt.innerHTML = field + "</br>" + jsonData;
}
function createJson(jsonObj, key, value){
if(typeof value === "undefined"){
delete jsonObj[key];
} else {
jsonObj[key] = value;
}
}
</script>
</body>
</html>
运行结果：
Demo4：
比较两个字符串不同的元素并打印出来，其中两个字符串是包含关系，即一个字符串一定是另一个字符串的子串，如{1,2,4}是{1,2,3,4,5}的子串
<html>
<head>
<title>IT-Homer demo</title>
</head>
<body>
<input type="button" id="parse" value="parse json" onclick="parseJson222()" />
<div id="txt" />
<script type="text/javascript">
function parseJson222(){
var txt = document.getElementById("txt");
// var jsonData_old = '_2,4,_4,21,_5,22,8,_7,23,_9,11,12,13,61';
// var jsonData_new = '_2,_3,1,2,3,4,_4,21,_5,22,_6,5,6,7,8,_7,23,_9,11,12,13,14,-1,61';
var jsonData_new = '_2,4,_4,21,_5,22,8,_7,23,_9,11,12,13,61';
var jsonData_old = '_2,_3,1,2,3,4,_4,21,_5,22,_6,5,6,7,8,_7,23,_9,11,12,13,14,-1,61';
var diff = diffJson(jsonData_old, jsonData_new);
txt.innerHTML = diff;
printArray("diff", diff);
}
function diffJson(jsonData_old, jsonData_new){
var diff = "";
var oldArray = jsonData_old.split(",");
var newArray = jsonData_new.split(",");
var oldLen = oldArray.length;
var newLen = newArray.length;
var minLen = Math.min(oldLen, newLen);
if(minLen == newLen){
tmpArray = newArray; // swap array
newArray = oldArray;
oldArray = tmpArray;
newLen = oldLen; // swap array length
oldLen = minLen;
}
printArray("newArray", newArray);
printArray("oldArray", oldArray);
var arr = [];
for(i=0; i<newLen; i++){
var j=0;
for(j=0; j<oldLen; j++){
if(newArray[i] == oldArray[j]){
break;
}
}
if(j == oldLen){
arr.push(newArray[i]);
}
}
return arr;
}
function printArray(tag, arr){
var len = arr.length;
document.write("<br>");
document.write(tag + " : " + arr.toString());
}
</script>
</body>
</html>
运行结果：
Demo5：
<html>
<head>
<title>hello</title>
<style type="text/css">
#adddelTextId{
float: clean;
}
normal {
font-style: normal;
color: #000000;
}
add {
font-style: normal;
color: #cc0000;
}
del {
font-style: normal;
color: #0000ff;
text-decoration: line-through;
}
</style>
</head>
<body onload="initLoad()">
<textarea id="textareaId" name="aaa" cols="50" rows="5" >
</textarea><br />
<div>
<div id="normalTextId" style="float:left">我,喜,欢</div>
<add><div id="addTextId" style="float:left">,你</div></add>
<del><div id="delTextId">,做,朋,友</div></del>
</div>
<input type="button" value="click me" onclick="hh()">
<script language="javascript">
var textareaId = document.getElementById("textareaId");
var adddelTextId = document.getElementById("adddelTextId");
var normalTextId = document.getElementById("normalTextId");
var addTextId = document.getElementById("addTextId");
var delTextId = document.getElementById("delTextId");
function initLoad(){
adddelText = normalTextId.innerHTML + addTextId.innerHTML;
textareaId.innerHTML = adddelText;
}
function hh(){
adddelTextFunc(true, ",IT-Homer");
adddelTextFunc(false, ",Sunboy_2050");
}
function adddelTextFunc(isAdd, txt){
if(isAdd){ // add
addTextId.innerHTML = txt;
} else { // del
delTextId.innerHTML = txt;
}
adddelText = normalTextId.innerHTML + addTextId.innerHTML;
textareaId.innerHTML = adddelText;
}
</script>
</body>
</html>
运行结果：
