Question

我是JavaScript新手并且正在练习。我试图显示在名称为＆＃34; test＆＃34;的div中的h1和p元素的组合高度。我查了各种各样的东西，感觉我真的很亲近，但是不能让它发挥作用。有人能帮忙吗？

HTML：

<div class="test">
    <h1>Understanding Scope</h1>
    <p>By understanding code's <em>scope</em>, we know when that code affects only one part of our code, or the entire codebase.  If we create things that are <em>global</em> in scope, we are giving any code the supreme power to control our code.   So we want to protect our code by being very careful when creating things that are global in scope. This is especially important if you plan on using JavaScript libraries like jQuery.</p>
</div>
<h1>Local Scope</h1>
<p>JavaScript uses <em>function scope</em>, meaning every time we create a new function the scope changes.  Any code inside that function is <em>local</em> to that function. Code that is local in scope is not accessible to outside code.</p>

JavaScript的：

function testing(){
    if (document.getElementsByClass('test')){
        var headerHeight = document.getElementsByTagName('h1').offsetHeight;
        var textHeight = document.getElementsByTagName('p').offsetHeight;
        var totalHeight = headerHeight + textHeight;

        alert(totalHeight);
    }
}

testing();

Answer 1

是document.getElementsByClassName，而不是getElementsByClass，你也得到了h1和p标签的数组

function testing(){
    if (document.getElementsByClassName('test')){
        var headerHeight = document.getElementsByTagName('h1')[0].offsetHeight;
        var textHeight = document.getElementsByTagName('p')[0].offsetHeight;
        var totalHeight = headerHeight + textHeight;

        alert(totalHeight);
    }
}

testing();

Answer 2

function testing(){
    if (document.getElementsByClassName('test')){

        var headerHeight = document.getElementsByTagName('h1')[0].offsetHeight;
        var textHeight = document.getElementsByTagName('p')[0].offsetHeight;
        var totalHeight = headerHeight + textHeight;

        alert(totalHeight);
    }
}

测试（）;

JavaScript - 如果使用.offsetHeight的语句不起作用

2 个答案: