javascript - 如何在我的程序上应用 localStorage 或 javascript Cookie？

Question

我研究了一些有关 localStorage 和 javascript cookie 的网站，并尝试应用它，但没有成功，它总是不起作用。我想在我的作业中应用 localStorage 或 javascript cookie。一个简单的预订主题。我希望浏览器记住我在浏览器中所做的更改。

Javascript:

<script type="text/javascript">
        var availableSlot1 = 5;
        var reduceSlot1 = function(valueToDeduct1){
            availableSlot1 = availableSlot1 - valueToDeduct1;
            document.getElementById('ite164').innerHTML = availableSlot1;
            if (availableSlot1 == 0){
                document.getElementById('ite164').innerHTML = "FULL";
                document.getElementById("ite164").style.color = "red";
                document.getElementById("number1").style.color = "red";
                document.getElementById("subject1").style.color = "red";
                document.getElementById("code1").style.color = "red";
                document.getElementById("units1").style.color = "red";
                document.getElementById("prof1").style.color = "red";
                document.getElementById("1").style.display = "none";
            }
        };
        var availableSlot2 = 5;
        var reduceSlot2 = function(valueToDeduct2){
            availableSlot2 = availableSlot2 - valueToDeduct2;
            document.getElementById('phi001').innerHTML = availableSlot2;
            if (availableSlot2 == 0){
                document.getElementById('phi001').innerHTML = "FULL";
                document.getElementById("phi001").style.color = "red";
                document.getElementById("number2").style.color = "red";
                document.getElementById("subject2").style.color = "red";
                document.getElementById("code2").style.color = "red";
                document.getElementById("units2").style.color = "red";
                document.getElementById("prof2").style.color = "red";
                document.getElementById("2").style.display = "none";
            }
        };
        var availableSlot3 = 5;
        var reduceSlot3 = function(valueToDeduct3){
            availableSlot3 = availableSlot3 - valueToDeduct3;
            document.getElementById('ite165').innerHTML = availableSlot3;
            if (availableSlot3 == 0){
                document.getElementById('ite165').innerHTML = "FULL";
                document.getElementById("ite165").style.color = "red";
                document.getElementById("number3").style.color = "red";
                document.getElementById("subject3").style.color = "red";
                document.getElementById("code3").style.color = "red";
                document.getElementById("units3").style.color = "red";
                document.getElementById("prof3").style.color = "red";
                document.getElementById("3").style.display = "none";
            }
        };
        var availableSlot4 = 5;
        var reduceSlot4 = function(valueToDeduct4){
            availableSlot4 = availableSlot4 - valueToDeduct4;
            document.getElementById('ite048').innerHTML = availableSlot4;
            if (availableSlot4 == 0){
                document.getElementById('ite048').innerHTML = "FULL";
                document.getElementById("ite048").style.color = "red";
                document.getElementById("number4").style.color = "red";
                document.getElementById("subject4").style.color = "red";
                document.getElementById("code4").style.color = "red";
                document.getElementById("units4").style.color = "red";
                document.getElementById("prof4").style.color = "red";
                document.getElementById("4").style.display = "none";
            }
        };
        var availableSlot5 = 5;
        var reduceSlot5 = function(valueToDeduct5){
            availableSlot5 = availableSlot5 - valueToDeduct5;
            document.getElementById('ite136').innerHTML = availableSlot5;
            if (availableSlot5 == 0){
                document.getElementById('ite136').innerHTML = "FULL";
                document.getElementById("ite136").style.color = "red";
                document.getElementById("number5").style.color = "red";
                document.getElementById("subject5").style.color = "red";
                document.getElementById("code5").style.color = "red";
                document.getElementById("units5").style.color = "red";
                document.getElementById("prof5").style.color = "red";
                document.getElementById("5").style.display = "none";
            }
        };

Jquery:

<script>
$(document).ready(function(){
            $("#button1").hide();
            $("#button2").hide();
            $("#button3").hide();
            $("#button4").hide();
            $("#button5").hide();
            $("#button6").hide();
            $("#button7").hide();
            $("#1").click(function(){
                $("#button1").show();
                $("#button1").fadeIn(1000);
                $("#button2").hide();
                $("#button3").hide();
                $("#button4").hide();
                $("#button5").hide();
                $("#button6").hide();
                $("#button7").hide();
                    $("#button1").click(function() {
                        $("#button1").hide();
                    });
              });
              $("#2").click(function(){
                $("#button1").hide();
                $("#button2").show();
                $("#button2").fadeIn(1000);
                $("#button3").hide();
                $("#button4").hide();
                $("#button5").hide();
                $("#button6").hide();
                $("#button7").hide();
                    $("#button2").click(function() {
                        $("#button2").hide();
                    });
              });
              $("#3").click(function(){
                $("#button1").hide();
                $("#button2").hide();
                $("#button3").show();
                $("#button3").fadeIn(1000);
                $("#button4").hide();
                $("#button5").hide();
                $("#button6").hide();
                $("#button7").hide();
                    $("#button3").click(function() {
                        $("#button3").hide();
                    });
              });
              $("#4").click(function(){
                $("#button1").hide();
                $("#button2").hide();
                $("#button3").hide();
                $("#button4").show();
                $("#button4").fadeIn(1000);
                $("#button5").hide();
                $("#button6").hide();
                $("#button7").hide();
                    $("#button4").click(function() {
                        $("#button4").hide();
                    });
              });
              $("#5").click(function(){
                $("#button1").hide();
                $("#button2").hide();
                $("#button3").hide();
                $("#button4").hide();
                $("#button5").show();
                $("#button5").fadeIn(1000);
                $("#button6").hide();
                $("#button7").hide();
                    $("#button5").click(function() {
                        $("#button5").hide();
                    });
              });
              $("#6").click(function(){
                $("#button1").hide();
                $("#button2").hide();
                $("#button3").hide();
                $("#button4").hide();
                $("#button5").hide();
                $("#button6").show();
                $("#button6").fadeIn(1000);
                $("#button7").hide();
                    $("#button6").click(function() {
                        $("#button6").hide();
                    });
              });
              $("#7").click(function(){
                $("#button1").hide();
                $("#button2").hide();
                $("#button3").hide();
                $("#button4").hide();
                $("#button5").hide();
                $("#button6").hide();
                $("#button7").show();
                $("#button7").fadeIn(1000);
                    $("#button7").click(function() {
                        $("#button7").hide();
                    });
              });
        });
</script>

HTML:

<table border="1" width="700px">
        <tr>
            <th>#</th>
            <th>Subjects</th>
            <th>Subject Code</th>
            <th>Units</th>
            <th>Instructor</th>
            <th>Available Slots</th>
        </tr>
        <tr>
            <td class="center" id="number1">1</td>
            <td id="subject1">Data Comm. Systems & Networking</td>
            <td class="center" id="code1">ITE164</td>
            <td class="center" id="units1">3.0</td>
            <td id="prof1">Quinito, Floreto Jr. R.</td>
            <td style="text-align: center;"><span id="ite164">5</span></td>
        </tr>
        <tr>
            <td class="center" id="number2">2</td>
            <td id="subject2">Introduction to Philosophy and Logic</td>
            <td class="center" id="code2">PHI001</td>
            <td class="center" id="units2">3.0</td>
            <td id="prof2">Chiong, Isidro R.</td>
            <td style="text-align: center;"><span id="phi001">5</span></td>
        </tr>
        <tr>
            <td class="center" id="number3">3</td>
            <td id="subject3">Basic Finance & Acctg. Principles for IT</td>
            <td class="center" id="code3">ITE165</td>
            <td class="center" id="units3">3.0</td>
            <td id="prof3">Cadelinia, Godofredo B.</td>
            <td style="text-align: center;"><span id="ite165">5</span></td>
        </tr>
        <tr>
            <td class="center" id="number4">4</td>
            <td id="subject4">Discrete Structures</td>
            <td class="center" id="code4">ITE048</td>
            <td class="center" id="units4">3.0</td>
            <td id="prof4">Calibara, Eunelfa Regie F.</td>
            <td style="text-align: center;"><span id="ite048">5</span></td>
        </tr>
        <tr>
            <td class="center" id="number5">5</td>
            <td id="subject5">Web Page Design</td>
            <td class="center" id="code5">ITE136</td>
            <td class="center" id="units5">3.0</td>
            <td id="prof5">Pequiro, Chemby Mae S.</td>
            <td style="text-align: center;"><span id="ite136">5</span></td>
        </tr>
        <tr>
            <td class="center" id="number6">6</td>
            <td id="subject6">Systems Analysis and Design</td>
            <td class="center" id="code6">ITE062</td>
            <td class="center" id="units6">3.0</td>
            <td id="prof6">Galudo, Darwin M.</td>
            <td style="text-align: center;"><span id="ite062">5</span></td>
        </tr>
        <tr>
            <td class="center" id="number7">7</td>
            <td id="subject7">Operating System</td>
            <td class="center" id="code7">ITE076</td>
            <td class="center" id="units7">3.0</td>
            <td id="prof7">Lagala, Glenn T.</td>
            <td style="text-align: center;"><span id="ite076">5</span></td>
        </tr>
    </table>
    <div id="combobox">
        <span style="color: white;">Select a subject to reserve:</span>
        <select>
          <option id="1" value="ITE164">Data Comm. Systems & Networking (ITE164)</option>
          <option id="2" value="PHI001">Introduction to Philosophy and Logic (PHI001)</option>
          <option id="3" value="ITE165">Basic Finance & Acctg. Principles for IT (ITE165)</option>
          <option id="4" value="ITE048">Discrete Structures (ITE048)</option>
          <option id="5" value="ITE136">Web Page Design (ITE136)</option>
          <option id="6" value="ITE062">Systems Analysis and Design (ITE062)</option>
           <option id="7" value="ITE076">Operating System (ITE076)</option>
        </select> 
         <a href="javascript:reduceSlot1(1)" id="button1"><input type="button" value="Reserve"></a>
         <a href="javascript:reduceSlot2(1)" id="button2"><input type="button" value="Reserve"></a>
         <a href="javascript:reduceSlot3(1)" id="button3"><input type="button" value="Reserve"></a>
         <a href="javascript:reduceSlot4(1)" id="button4"><input type="button" value="Reserve"></a>
         <a href="javascript:reduceSlot5(1)" id="button5"><input type="button" value="Reserve"></a>
         <a href="javascript:reduceSlot6(1)" id="button6"><input type="button" value="Reserve"></a>
         <a href="javascript:reduceSlot7(1)" id="button7"><input type="button" value="Reserve"></a>
    </div>

很抱歉代码非常困惑，我还是个新手。你能帮我吗？

Answer 1

本地存储将比 cookie 更好地满足您的需求。基本上，窗口上有一个名为 localStorage 的类似数组的对象。您只能使用它来存储任意字符串。喜欢:

window.localStorage["button1_is_showing"] = true;

或者:

window.localstorage.button1_is_showing = true;

true bool 值将转换为字符串 "true"。一段时间后再次将其转换为 bool 值:

var b1showing;
if (window.localStorage.button1_is_showing == "true") {
    b1showing = true;
}
else {
    b1showing = false;
}

您还可以使用浏览器的 JSON 解析器来实现此目的:

var b1showing = JSON.parse(window.localStorage.button1_is_showing);

但请记住，它没有强大的浏览器支持:http://caniuse.com/#search=JSON

您在 localStorage 中存储的任何字符串都将保留在那里，直到浏览器清除其 cookie，或者直到您删除如下内容:

delete window.localStorage.b1showing;

对于您的特定示例:每次用户单击按钮时，请在 localStorage 中为每个按钮创建一个对象来存储按钮状态。然后，当加载页面时(在就绪事件中)，循环遍历本地存储检查那里有什么，并根据情况隐藏/显示按钮。

旁注:使用类而不是 7 个不同的 id 更加灵活、可读且快速。

编辑:另一个优秀来源:http://diveintohtml5.info/storage.html

这里有更多信息:https://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Storage