输入框占位符animation怎么做

Question

I seen this on a website, where the placeholder text "Pounds" remains on top of input box. Example:

How exactly is that accomplished?

  <div id="my-ajax-filter-search">
        <form action="" method="post">
            <label id="label-lg">Weight</label>
            <input type="text" name="search" id="search" value="" >
            <input type="submit" id="submit" name="submit" value="See shipping rates" />
        </form>
        <ul ></ul>
<section class="elementor-section elementor-inner-section elementor-element elementor-element-784a76e1 elementor-section-boxed elementor-section-height-default elementor-section-height-default" data-id="784a76e1" data-element_type="section">
        <div id="ajax_filter_search_results" class="elementor-container elementor-column-gap-no np-wrap">
 
            </div>
</section>
    </div>

CSS:

.input-text {
    min-width: 84px;
}div#my-ajax-filter-search input#search , label#label-lg {
    max-width: 250px;
    margin: 0 auto;
    display: block;
    border-radius: 5px;
}
label#label-lg {
    color: #fff;
    margin-bottom: 6px;
    font-weight: bold;
}
div#my-ajax-filter-search input#submit:focus {
    outline: none;
}
div#my-ajax-filter-search input#submit {
    max-width: 192px;
    display: block;
    width: 100%;
    margin: 15px auto;
    background: #fff;
    font-family: "Montserrat", Sans-serif;
    fill: #373278;
    color: #373278;
    background-color: #ffffff;
    border-style: solid;
    border-width: 1px 1px 1px 1px;
    border-color: #ffffff;
    border-radius: 50px 50px 50px 50px;
    box-shadow: 0px 10px 30px -8px rgb(0 0 0 / 16%);
}

div#my-ajax-filter-search input#submit:hover {
    color: #ffffff;
    background-color: rgba(255,255,255,0);
    border-color: #ffffff;
}


.elementor-price-table__feature-inner input {
    min-width: 1px;
}

.elementor-2 .elementor-element.elementor-element-1257087d .elementor-price-table__feature-inner {
    margin: 0;
}

.elementor-2 .elementor-element.elementor-element-1257087d .elementor-price-table__feature-inner .quantity {
    max-width: 67px;
    margin: 0 auto;
}

.elementor-2 .elementor-element.elementor-element-1257087d .elementor-price-table__feature-inner a.add_cart.button.product_type_simple {
    max-width: 106px;
    margin: 12px auto;
    display: block;
    padding: 17px;
    border-radius: 10px;
    border: 1px solid;
    background: #00a8ff;
    color: #fff;
}

Answer 1

You can use this code

 body { font-family: sans-serif; }.label-before, .field input:focus + label::before, .field input:valid + label::before { line-height: 15px; font-size: 12px; top: 5px; background: #fff; padding: 0 6px; left: 9px; }.field { position: relative; margin-bottom: 15px; margin-top:10px; display:inline-block; }.field label::before { content: attr(title); position: absolute; top: 10px; left: 15px; line-height: 30px; font-size: 14px; color: #777; transition: 300ms all; }.field input { width: auto; height: 50px; padding: 0px 15px; padding-top:12px; box-sizing: border-box; font-size: 14px; color: #222; border: 1px solid #ccc; border-radius: 3px; text-align: center; }.field input:focus { outline: 0; border-color: blue; }.field input:valid + label::before { content: attr(data-title); }.field input:focus + label::before { color: blue; }

 <div id="my-ajax-filter-search"> <form action="" method="post"> <div class="control-group"> <div> <label id="label-lg">Weight</label> </div> <div class="field"> <input type="text" required autocomplete="off" name="search" id="search" value="" > <label for="search" title="Pounds" data-title="Pounds"></label> </div> </div> <input type="submit" id="submit" name="submit" value="See shipping rates" /> </form> <ul ></ul> <section class="elementor-section elementor-inner-section elementor-element elementor-element-784a76e1 elementor-section-boxed elementor-section-height-default elementor-section-height-default" data-id="784a76e1" data-element_type="section"> <div id="ajax_filter_search_results" class="elementor-container elementor-column-gap-no np-wrap"> </div> </section> </div>