Max。文本的行数;该方法可靠吗?-Max.numberoftextlines;Isthismethodreliable?

8  

Your method will work, sure, but there is only one thing: if you write down a word that exceeds the 400px width then it will overflow horizontally. To fix this, you just need to add word-wrap: break-word and white-space: pre to the CSS rules.

当然，你的方法是有效的，但是只有一件事:如果你写下一个超过400px的单词，那么它就会水平溢出。为了解决这个问题，您只需要添加单词-wrap: break-word和white-space: preto CSS规则。

2  

If your question is about "user agent CSS stylesheet" and override it, then use the !important rule behind your em units rules and set the box-sizing that suits your code :

如果你的问题是关于“用户代理CSS样式表”并覆盖它，那么使用!

h3 {
    width: 400px;
    font-size: 1.5em !important;
    max-height: 2.4em !important;
    line-height: 1.2em !important;
    overflow-y: hidden;/* see @Marco Bonnelli answer to improve this part */
    /* perhaps throw in some padding and margin control to be sure 
     - box-sizing ? */
    box-sizing:content-box !important;/* so no matter if there is borders or padding */
}

!important should be used when you do have no other option, else it can drive you nuts :).

重要的东西应该在你别无选择的时候使用，否则会让你发疯。