Javascript 如果本地存储器为空,则显示消息
我发现了javascript代码,它用于将生日数据存储到本地存储器并在div中显示数据。 现在,如果存储空间为空,则不显示任何内容。 但我需要,如果本地存储为空,则显示一条消息,例如;“先定你的生日” 在下面的div中显示数据 多谢大家Javascript 如果本地存储器为空,则显示消息,javascript,json,Javascript,Json,我发现了javascript代码,它用于将生日数据存储到本地存储器并在div中显示数据。 现在,如果存储空间为空,则不显示任何内容。 但我需要,如果本地存储为空,则显示一条消息,例如;“先定你的生日” 在下面的div中显示数据 多谢大家 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.3.2.js"></script>
</head>
<body>
<script>
$(function storeDates(form){
var operation = "A"; //"A"=Adding; "E"=Editing
var selected_index = -1; //Index of the selected list item
var tbClients = localStorage.getItem("tbClients");//Retrieve the stored data
tbClients = JSON.parse(tbClients); //Converts string to object
if(tbClients == null) //If there is no data, initialize an empty array
tbClients = [];
function Add(){
var client = JSON.stringify({
birthday : $("#birth_day").val(),
patientno:$("#patient_no").val()
});
tbClients.push(client);
localStorage.setItem("tbClients", JSON.stringify(tbClients));
return true;
}
function Edit(){
tbClients[selected_index] = JSON.stringify({
ID : $("#name").val(),
});//Alter the selected item on the table
localStorage.setItem("tbClients", JSON.stringify(tbClients));
alert("The data was edited.")
operation = "A"; //Return to default value
return true;
}
function Delete(){
tbClients.splice(selected_index, 1);
localStorage.setItem("tbClients", JSON.stringify(tbClients));
alert("Client deleted.");
}
function List(){
$("#tblList").html("");
$("#tblList").html(
"<thead>"+
" <tr>"+
" <th></th> "+
" </tr>"+
"</thead>"+
"<tbody>"+
"</tbody>"
);
for(var i in tbClients){
var cli = JSON.parse(tbClients[i]);}
$("#tblList tbody").append("<tr>"+
" <td ><span class='dayText'><b class='dayclass'>"+
"Birth day"+cli.birthday + "</td>" +
"</tr>");
$("#patient_number").append(cli.patientno );
}
$("#frmCadastre").bind("submit",function(){
if(operation == "A")
return Add();
else
return Edit();
});
List();
$(".btnEdit").bind("click", function(){
operation = "E";
selected_index = parseInt($(this).attr("alt").replace("Edit", ""));
var cli = JSON.parse(tbClients[selected_index]);
$("#deliveryday").val(cli.ID);
});
$(".btnDelete").bind("click", function(){
selected_index = parseInt($(this).attr("alt").replace("Delete", ""));
Delete();
List();
});
});
</script>
<FORM name="f1" id="frmCadastre" >
<section id="aligned">
<input type="text" id="birth_day" name="birth_day" placeholder=" Birth day :" autocomplete="off" tabindex="2" class="txtinput" required><br/><br/>
<input type="text" id="patient_no" name="patient_no" placeholder=" patient no" autocomplete="off" tabindex="2" class="txtinput" required><br/><br/>
<input type="submit" name="submit" id="btnSave" class="submitbtn" tabindex="7" onClick="storeDates(this.form); " />
</form>
<div id="tblList"></div>
<div id="patient_number"></div>
</body>
</html>
无标题文件
$(函数存储日期(表格){
var operation=“A”/“A”=添加;“E”=编辑
var selected_index=-1;//所选列表项的索引
var tbClients=localStorage.getItem(“tbClients”);//检索存储的数据
tbClients=JSON.parse(tbClients);//将字符串转换为对象
if(tbClients==null)//如果没有数据,则初始化空数组
tbClients=[];
函数Add(){
var client=JSON.stringify({
生日:$(“#出生日”).val(),
病人编号:$(“#病人编号”).val()
});
tbClients.push(客户机);
setItem(“tbClients”,JSON.stringify(tbClients));
返回true;
}
函数编辑(){
tbClients[selected_index]=JSON.stringify({
ID:$(“#名称”).val(),
});//更改表上的选定项
setItem(“tbClients”,JSON.stringify(tbClients));
警报(“数据已编辑。”)
operation=“A”;//返回默认值
返回true;
}
函数Delete(){
TBU.拼接(选定的索引,1);
setItem(“tbClients”,JSON.stringify(tbClients));
警报(“客户已删除”);
}
函数列表(){
$(“#tblList”).html(“”);
$(“#tblList”).html(
""+
" "+
" "+
" "+
""+
""+
""
);
用于(TBClient中的var i){
var cli=JSON.parse(tbClients[i]);}
$(“#tblList tbody”).append(”+
" "+
“生日”+cli.Birth+“”+
"");
$(“#患者编号”).append(cli.patientno);
}
$(“#frmCadastre”).bind(“submit”,function(){
如果(操作==“A”)
返回Add();
其他的
返回编辑();
});
List();
$(“.btnEdit”).bind(“单击”,函数(){
操作=“E”;
所选的_index=parseInt($(this).attr(“alt”).replace(“Edit”,”);
var cli=JSON.parse(tbClients[selected_index]);
$(“#deliveryday”).val(cli.ID);
});
$(“.btnDelete”).bind(“单击”,函数(){
所选的_index=parseInt($(this).attr(“alt”).replace(“Delete”,”);
删除();
List();
});
});
用以下代码替换部分代码:
if (cli.birthday <> "" ) {
$("#tblList tbody").append("<tr>" +
" <td ><span class='dayText'><b class='dayclass'>" +
"Birth day : Set Birthday First</td>" +
"</tr>");
}
else {
$("#tblList tbody").append("<tr>" +
" <td ><span class='dayText'><b class='dayclass'>" +
"Birth day" + cli.birthday + "</td>" +
"</tr>");
}
if(cli.birth“”){
$(“#tblList tbody”).append(”+
" " +
“生日:将生日设置为第一”+
"");
}
否则{
$(“#tblList tbody”).append(”+
" " +
“生日”+cli.Birth+“”+
"");
}
首先,如何通过本地存储工作
if(!localStorage.tbClients) alert("Empty");
获取数据的另一种方法
if(!localStorage.getItem("tbClients")) alert("Empty");
这两种方法之间的区别:
//getting value
var message = localStorage.getItem("SOME_KEY") || "Firstly save your value to localStorage";
console.log(message);
// if user already save something in localStorage we will see it, otherwise "Firstly save your value to localStorage"
1.只需将数据与“”进行比较,如果其相等,则设置yr msg else以显示日期。将本地存储数据的长度与0进行比较。如果相等,则显示yr msg。