javascript - 为什么我无法禁用按钮？

Question

我花了几个小时尝试在这个简短的脚本中禁用一个简单的 javascript 按钮 (id="storeButton")。我已经尝试了在互联网上找到的各种语法变体来实现这一效果，但无济于事。我正在 WordPress 页面中执行此操作。有人可以告诉我我的错误是什么吗？

WordPress 页面:

<p style="text-align: center;">Welcome!</p>
<strong>What is this project, and why contribute?</strong>

text

&nbsp;

<script src="/scripts/alert.js" type="text/javascript"></script>
<script src="/webcamjs/webcam.js" type="text/javascript"></script>
<script src="/scripts/take_snapshot.js" type="text/javascript"></script>

<div class="centre" id="my_camera" style="width:320px; height:240px;"></div>
<br>
<div id="freezeButton"></div>
<div id="storeButton"></div>
<br>
<div id="my_result"></div>

<script type="text/javascript">
<!--
ShowAlert();
webcamConfigure();
attach();
createFreezeButton();
disableBtn();
createStoreButton();
//-->
</script>

take_snapshot.js，问题似乎出在此处

document.getElementById("storeButton").disabled = true;:

function webcamConfigure(){
    Webcam.set({
        width: 320,
        height: 240,
        dest_width: 640,
        dest_height: 480,
        image_format: 'jpeg',
        jpeg_quality: 100,
        force_flash: true
    });
}

function attach(){
    Webcam.attach( '#my_camera' );
}

function createStoreButton(){
    sendButton = document.createElement("input");
    sendButton.type = "button";
    sendButton.value = "Send snapshot!";
    sendButton.onclick = function store(){
        Webcam.snap( function(data_uri) {
            document.getElementById('my_result').innerHTML = '<img src="'+data_uri+'"/>';
        } );
    }
    placeHolder = document.getElementById("storeButton");
    placeHolder.appendChild(sendButton);
}

function disableBtn(){
    document.getElementById("storeButton").disabled = true;
}

function createFreezeButton(){
    myButton = document.createElement("input");
    myButton.type = "button";
    myButton.value = "Take snapshot!";
    myButton.onclick = function freeze(){
        if (myButton.value=="Take snapshot!") {
            myButton.value = "Discard snapshot!";
            Webcam.freeze();
            //document.getElementById("storeButton").disabled = false;
        }
        else {
            myButton.value = "Take snapshot!";
            Webcam.unfreeze();
            //document.getElementById("storeButton").disabled = true;
        }
    }
    placeHolder2 = document.getElementById("freezeButton");
    placeHolder2.appendChild(myButton);
}

Answer 1

您正在尝试禁用名为“storeButton”的 div，而不是禁用您创建的包含在该 div 内的按钮。在您的上下文中，一种简单的方法是在创建按钮时使用公共(public)变量，当您想要禁用它时可以使用该变量:

var sendButton;
function webcamConfigure(){
    Webcam.set({
        width: 320,
        height: 240,
        dest_width: 640,
        dest_height: 480,
        image_format: 'jpeg',
        jpeg_quality: 100,
        force_flash: true
    });
}

function attach(){
    Webcam.attach( '#my_camera' );
}

function createStoreButton(){
    sendButton = document.createElement("input");
    sendButton.type = "button";
    sendButton.value = "Send snapshot!";
    sendButton.onclick = function store(){
        Webcam.snap( function(data_uri) {
            document.getElementById('my_result').innerHTML = '<img src="'+data_uri+'"/>';
        } );
    }
    placeHolder = document.getElementById("storeButton");
    placeHolder.appendChild(sendButton);
}

function disableBtn(){
    sendButton.disabled = true;
}

希望这有帮助，

:) 大卫