Question

在javascript中，我正在创建新的图像标记，我正在使用setAttribute（）方法向它们添加属性，但我发现如果我添加一个onclick事件并添加一个函数，我就无法在参数中设置如下所示

count = 0; //Will be the number that will go into parameter for function
function start() {
imageTag = document.createElement("IMG"); //Creates image tag
imageTag.setAttribute("src", "popo.jpg"); //sets the image tags source
count++; //as the start function keeps getting called, count will increase by 1 and the parameter for each function in each individual image tag will increase by one
imageTag.setAttribute("onclick", "disappear(count)"); //this will add the onclick attribute with the function disappear() and the parameter inside which will be a number that will increase as the start function is called again and the image tag is called again *ERROR*
document.body.appendChild(imageTag); //appends the image tag created
}

问题是，当创建每个新图像标记时，它实际上只是创建

<img src = "popo.jpg" onclick = "disappear(count)"/>

我希望它更像是

<img src = "popo.jpg" onclick = "disappear('1')"/>
<img src = "popo.jpg" onclick = "disappear('2')"/> //and so on...

Answer 1

在函数中添加count作为param，而不是字符串。

count = 0; //Will be the number that will go into parameter for function
function start() {
    imageTag = document.createElement("IMG"); //Creates image tag
    imageTag.setAttribute("src", "popo.jpg"); //sets the image tags source
    count++; //as the start function keeps getting called, count will increase by 1 and the parameter for each function in each individual image tag will increase by one
    imageTag.setAttribute("onclick", "disappear("+count+")"); //this will add the onclick attribute with the function disappear() and the parameter inside which will be a number that will increase as the start function is called again and the image tag is called again *ERROR*
    document.body.appendChild(imageTag); //appends the image tag created
}

Answer 2

不使用点击事件作为属性添加，而是使用 addEventListener

添加它

imageTag.addEventListener("click", disappear.bind(null, count));

Bind 会在调用时使count可用于此功能。

然后创建一个消失函数

function disappear(ID){
  alert(ID); // This should give the count.
}

Answer 3

由于您使用的是setAttribute，因此您设置了event handler content attribute。相应的事件处理程序设置为internal raw uncompiled handler。该代码的范围将是

全局对象
文件
表单所有者（如果有）
元素（如果有）

如果您的count变量在任何这些范围内都不可用，那么它将无法正常工作。即使它可用，因为你不断增加它，所使用的值将是修改后的值。

你不想要那个。相反，你可以：

在未编译的处理程序中写入变量：

imageTag.setAttribute("onclick", "disappear(" + count + ")");

使用event handler IDL attributes，例如

var localCount = count; // Using a local copy in case `count` is modified
imageTag.onclick = function() {
    disappear(localCount);
};

如何在javascript中的setAttribute（）方法中将参数添加到函数中

3 个答案: