可见时激活 CSS 动画

Question

I am using a CSS animation on my webpage, this animation is in the middle of my page. Its animation starts as soon as I visit the webpage. So the user is not able to see it, I have tried few solutions provided on the internet but none of it seems to work for me.

 .pcb-text { display: flex; justify-content: center; align-items: center; } .pcb-text p { font-size: 35px; animation: typing 2s steps(45), blink-caret 0.85s step-end infinite; overflow: hidden; white-space: nowrap; margin: 0 auto; border-right: .12em solid orange; } @keyframes typing { from { width: 0; } to { width: 100%; } } /* The typewriter cursor effect */ @keyframes blink-caret { from, to { border-color: transparent } 50% { border-color: orange; } }

 <div class="pcb-text" id="animated_text"> <div class="text-center"> <p>Some Text Here</p> </div> </div>

I am new to this, so I would really appreciate that if you are giving an answer which includes JS or JQuery, please use a simple method which I can understand

Answer 1

You could put the animation in a separate class, and add this class when the element is scrolled into view.

This can be done with jQuery by adding a custom function that detects when the element is in view, and trigger this function every time the user scrolls.

 // function to detect if an element is scrolled into view function isScrolledIntoView(elem) { var docViewTop = $(window).scrollTop(); var docViewBottom = docViewTop + $(window).height(); var elemTop = $(elem).offset().top; var elemBottom = elemTop + $(elem).height(); return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop)); }; // listen for scroll event $(window).scroll(function () { // check if element is scrolled into view if (isScrolledIntoView($('#animated_text'))) { // element is scrolled into view, add animation class $('#animated_text').addClass('animation'); } });

 .pcb-text { display: flex; justify-content: center; align-items: center; } .pcb-text p { font-size: 35px; overflow: hidden; white-space: nowrap; margin: 0 auto; border-right: .12em solid orange; } /* move animation to separate class */ .animation p { animation: typing 2s steps(45), blink-caret 0.85s step-end infinite; } @keyframes typing { from { width: 0; } to { width: 100%; } } /* The typewriter cursor effect */ @keyframes blink-caret { from, to { border-color: transparent } 50% { border-color: orange; } }

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <div style="height: 1000px"></div> <div class="pcb-text" id="animated_text"> <div class="text-center"> <p>Some Text Here</p> </div> </div>