Dynamically changing content of a SPAN

问题

How can I dynamically change the content of a <span> tag in an infinite loop.

I have tried using the below method. Is it possible to do this with pure CSS animations? If it is not possible with pure CSS, please suggest an alternate method.

HTML:

<p>Lorem ipsum <span></span> sit amet.</p>

CSS:

span {
    content: '';
    animation: flip 2s infinite;
}
@keyframes flip {
    10% {
        content: 'Example no1';
    }
    40% {
        content: '';
    }
    80% {
        content: 'Example no2';
    }
    100% {
        content: '';
    }
}

Demo Fiddle

回答1:

Changing the content of a span dynamically using the content property is not possible. It was originally designed to be used only with pseudo-elements (like :before or :after).

However, this can be achieved with just HTML and Javascript like shown below:

var i = 0; // The counter variable
var arrayLength = 5; // The max length of the data array 
var dataArray = ['Example 1', 'Example 2', 'Example 3', 'Example 4', 'Example 5']; // The actual data which have to be shown in a loop

function changeval() {
    if (i == arrayLength) i = 0; // If counter reaches max length, reset it
    document.getElementById('dataSpan').innerHTML = dataArray[i]; // Set the value to the span
    i++; // Increment counter
}

setInterval(changeval, 500); // Call the function to change value at defined intervals

<!-- Just add an ID to your span to which the content must be set -->
<p>Lorem ipsum <span id='dataSpan'></span> sit amet.</p>

---

Though CSS isn't the best for your case, the below can be achieved using a few CSS tricks/hacks if the no. of items in your array is small/finite.

body, html{
    font-size: 16px;
}
#dataSpan {
    height: 1.25em;
    overflow: hidden;
    display: inline-block;
    vertical-align: top;
    padding: 0px;
    line-height: 1.25em;
    top:0;
}
#dataSpan span {
    position: relative;
    -webkit-animation: changeContent 5s steps(4) infinite;
    -moz-animation: changeContent 5s steps(4) infinite;
    animation: changeContent 5s steps(4) infinite;
}
@-webkit-keyframes changeContent {
    from{top:0;}
    to {top:-5em;}
}
@-moz-keyframes changeContent {
    from{top:0;}
    to {top:-5em;}
}
@keyframes changeContent {
    from{top:0;}
    to {top:-5em;}
}

<p>Lorem ipsum <span id="dataSpan">
        <span>Example 1<br>Example 2<br>Example 3<br>Example 4<br>Example 5</span>
</span> sit amet.</p>

来源：https://stackoverflow.com/questions/24488501/dynamically-changing-content-of-a-span