Strikethrough is used on content that is no longer considered relevant. Like a previous price tag on a now discounted sales item:
Discounted Product
Intel, 2TB SSD Drive
$99
In the now deprecated HTML4, we used the <strike> tag on content that was no longer considered relevant. In modern HTML, namely HTML5, we use the shorter <s> tag instead. The strikethrough in the example above looks like this:
<s>$249</s>Good to know
Don’t confuse the <s> tag with the <del> tag.
<s>represents content that is no longer accurate or relevant right now — as a price tag on a discounted product.<del>indicates that something was removed from your document, like a completed item on a todo list.