Pen Settings

HTML

CSS

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

+ add another resource

JavaScript

Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Packages

Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

Behavior

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML

              
                <div class="content">

    <h2>Dashed border using <span>background-image</span> property</h2>
    
    <p>
        Creating dashed borders with background-image is not a new concept. Many people use it because it allows full flexibility, and with a little creativity (and a few lines of code) it is possible to do cool things without it being too complicated.
    </p>

    <div class="boxes">
        <div class="box box-a">Simple</div>
        <div class="box box-b">Slanted</div>
        <div class="box box-c">Dotted</div>
        <div class="box box-d">Long</div>
        <div class="box box-e">Cornered</div>
        <div class="box box-f">Centered</div>
        <div class="box box-g">Faded</div>
        <div class="box box-h">Animated</div>
    </div>

    <hr>

    <h2>Create your own <span>background-image</span> border</h2>
    
    <div class="generator">

        <form>

            <Label>
                Border width
                <input name="borderWidth" type="range" class="input" min="1" max="10" value="3">
            </Label>

            <Label>
                Border color<br>
                <input name="borderColor" type="color" class="input" value="#333333">
            </Label>

            <Label>
                Dash length
                <input name="dashLength" type="range" class="input" min="1" max="30" value="10">
            </Label>

            <Label>
                Spacing
                <input name="spacing" type="range" class="input" min="1" max="30" value="10">
            </Label>

            <Label>
                Slanting angle
                <input name="slanting" type="range" class="input" min="-60" max="60" value="0">
            </Label>

            <Label>
                Fade
                <input name="borderFade" type="range" class="input" min="0" max="100" value="0">
            </Label>

            <Label>
                <input name="diraction" type="checkbox">
                Flip diraction
            </Label>

            <Label>
                Animation
                <input name="animation" type="range" class="input" min="0" max="1" step="0.1" value="0">
            </Label>

        </form>

        <div class="result"></div>

    </div>
</div>

<a href="https://twitter.com/amit_sheen" class="twitterLink" target="_blank">
   <img src="https://assets.codepen.io/1948355/twitterLogo2.png" />
</a>

              
            
!

CSS

              
                @import url('https://fonts.googleapis.com/css2?family=Open+Sans+Condensed:wght@300;700&display=swap');

*, *::before, *::after {
    padding: 0;
    margin: 0 auto;
    box-sizing: border-box;
}

body {
    font-family: 'Open Sans Condensed', sans-serif;
    min-height: 100vh;
    background-color: #eee;
    background-size: 10px 10px;
    background-image:
        radial-gradient(circle at 50% 50%, #ddd, #ddd 1px, transparent 1px),
        radial-gradient(circle at 0 0, #ddd, #ddd 1px, transparent 1px),
        radial-gradient(circle at 0 100%, #ddd, #ddd 1px, transparent 1px),
        radial-gradient(circle at 100% 0, #ddd, #ddd 1px, transparent 1px),
        radial-gradient(circle at 100% 100%, #ddd, #ddd 1px, transparent 1px);
    color: #333;
}

:root {
    --clr-border: #333;
    --AnimationLength: 0px;
}

.content {
    width: 100%; max-width: 960px;
    padding: 2em 2em 10em;
}

h2 {
    margin: 1em auto;
    text-decoration: underline;
    text-decoration-color: #aaa;

    & span {
        color: #777;
    }
}

p { 
    margin: 2em auto;
    font-weight: bold;
}

hr {
    height: 3px;
    border: none;
    margin: 4em auto;
    background-color: #aaa;
}

.boxes {
    width: 100%;
    display: grid;
    grid-gap: 2em;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
}

.box {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%; height: 123px;
    font-size: 2em;
    padding: 0.5em;
    line-height: 1;
    background-position:  0 0, 0 0, 100% 0, 0 100%;
    background-size: 3px 100%, 100% 3px, 3px 100% , 100% 3px;
    background-repeat: no-repeat;
}

.box-a { // Simple
    background-image:
        repeating-linear-gradient(0deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // left
        repeating-linear-gradient(90deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // top
        repeating-linear-gradient(180deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // right
        repeating-linear-gradient(270deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px) // bottom
    ;
    border-image: repeating-linear-gradient(0deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px);
}

.box-b { // Slanted
    background-image:
        repeating-linear-gradient(45deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // left
        repeating-linear-gradient(135deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // top
        repeating-linear-gradient(225deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // right
        repeating-linear-gradient(315deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px) // bottom
    ;
}

.box-c { // Dotted
    background-image:
        repeating-linear-gradient(0deg, var(--clr-border), var(--clr-border) 3px, transparent 3px, transparent 6px), // left
        repeating-linear-gradient(90deg, var(--clr-border), var(--clr-border) 3px, transparent 3px, transparent 6px), // top
        repeating-linear-gradient(180deg, var(--clr-border), var(--clr-border) 3px, transparent 3px, transparent 6px), // right
        repeating-linear-gradient(270deg, var(--clr-border), var(--clr-border) 3px, transparent 3px, transparent 6px) // bottom
    ;
}

.box-d { // Long
    background-image:
        repeating-linear-gradient(0deg, var(--clr-border), var(--clr-border) 30px, transparent 30px, transparent 36px), // left
        repeating-linear-gradient(90deg, var(--clr-border), var(--clr-border) 30px, transparent 30px, transparent 36px), // top
        repeating-linear-gradient(180deg, var(--clr-border), var(--clr-border) 30px, transparent 30px, transparent 36px), // right
        repeating-linear-gradient(270deg, var(--clr-border), var(--clr-border) 30px, transparent 30px, transparent 36px) // bottom
    ;
}

.box-e { // Cornered
    background-image:
        linear-gradient(0deg, var(--clr-border), var(--clr-border) 25%, transparent 25%, transparent 75%, var(--clr-border) 75%), // left
        linear-gradient(90deg, var(--clr-border), var(--clr-border) 25%, transparent 25%, transparent 75%, var(--clr-border) 75%), // top
        linear-gradient(180deg, var(--clr-border), var(--clr-border) 25%, transparent 25%, transparent 75%, var(--clr-border) 75%), // right
        linear-gradient(270deg, var(--clr-border), var(--clr-border) 25%, transparent 25%, transparent 75%, var(--clr-border) 75%) // bottom
    ;
}

.box-f { // Centered
    background-image:
        linear-gradient(0deg, transparent 15%, var(--clr-border) 15%, var(--clr-border) 85%, transparent 85%), // left
        linear-gradient(90deg, transparent 15%, var(--clr-border) 15%, var(--clr-border) 85%, transparent 85%), // top
        linear-gradient(180deg, transparent 15%, var(--clr-border) 15%, var(--clr-border) 85%, transparent 85%), // right
        linear-gradient(270deg, transparent 15%, var(--clr-border) 15%, var(--clr-border) 85%, transparent 85%) // bottom
    ;
}

.box-g { // Faded
    background-image:
        repeating-linear-gradient(0deg, var(--clr-border), var(--clr-border) 10px, transparent 20px, transparent 30px, var(--clr-border) 40px), // left
        repeating-linear-gradient(90deg, var(--clr-border), var(--clr-border) 10px, transparent 20px, transparent 30px, var(--clr-border) 40px), // top
        repeating-linear-gradient(180deg, var(--clr-border), var(--clr-border) 10px, transparent 20px, transparent 30px, var(--clr-border) 40px), // right
        repeating-linear-gradient(270deg, var(--clr-border), var(--clr-border) 10px, transparent 20px, transparent 30px, var(--clr-border) 40px) // bottom
    ;
}

.box-h { // Animated
    background-image:
        repeating-linear-gradient(0deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // left
        repeating-linear-gradient(90deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // top
        repeating-linear-gradient(180deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px), // right
        repeating-linear-gradient(270deg, var(--clr-border), var(--clr-border) 10px, transparent 10px, transparent 20px) // bottom
    ;
    background-size: 3px calc(100% + 20px), calc(100% + 20px) 3px, 3px calc(100% + 20px) , calc(100% + 20px) 3px;
    animation: boxBorderAnimation 1s infinite linear;

    @keyframes boxBorderAnimation {
        from { background-position:  0 0, -20px 0, 100% -20px, 0 100%; }
        to { background-position:  0 -20px, 0 0, 100% 0, -20px 100%; }
    }
}

// Generator:

.generator {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    grid-gap: 3em;

    @media (max-width: 768px) {
        grid-template-columns: 1fr;
    }

}

form {
    width: 100%;

    label {
        display: block;
        font-weight: bold;
        width: 100%;

        & + label {
            margin-top: 1.5em;
        }
    }
    
    .input {
        display: block;
        width: 100%;
    }
}

.result {
    width: 100%;
    height: 100%;
    padding: 1em;
    line-height: 1.2;
    background-repeat: no-repeat;

    span {
        display: block;
        padding-left: 4em;
        text-indent: -2em;
        margin: 0.5em auto;
    }

    @keyframes borderAnimation {
        from { background-position:  0 0, var(--AnimationLength) 0, 100% var(--AnimationLength), 0 100%; }
        to { background-position:  0 var(--AnimationLength), 0 0, 100% 0, var(--AnimationLength) 100%; }
    }
}

.twitterLink {
  position: fixed;
  bottom: 0.5em; right: 0.5em;
  & img {
    width: 2em;
    filter: grayscale(100%);
    transition: filter 0.25s;
    &:hover {
      filter: grayscale(0%);
    }
  }
}
              
            
!

JS

              
                function _(e, all=false) {
    let divs = document.querySelectorAll(e);
    if (all || (divs.length > 1)) { return divs; }
    return divs[0];
}

_('input', true).forEach(element => {
    element.addEventListener('input', drawBordr);
});

const resultDiv = _('.result');

drawBordr();
function drawBordr() {

    let borderWidth = Number(_('[name="borderWidth"]').value);
    let color1 = _('[name="borderColor"]').value;
    let dashLength = Number(_('[name="dashLength"]').value);
    let spacing = Number(_('[name="spacing"]').value);
    let slanting = Number(_('[name="slanting"]').value);
    let borderFade = 100 - Number(_('[name="borderFade"]').value);
    let diraction = _('[name="diraction"]').checked;
    let animation = Number(_('[name="animation"]').value);

    let color2 = 'transparent';

    const backgroundImage = `
        repeating-linear-gradient(${slanting + (diraction ? 180 : 0) }deg, ${color1}, ${color1} ${Math.round(dashLength * borderFade) / 100}px, ${color2} ${dashLength}px, ${color2} ${dashLength + (Math.round(spacing * borderFade) / 100)}px, ${color1} ${dashLength + spacing}px),
        repeating-linear-gradient(${slanting + (diraction ? 270 : 90)}deg, ${color1}, ${color1} ${Math.round(dashLength * borderFade) / 100}px, ${color2} ${dashLength}px, ${color2} ${dashLength + (Math.round(spacing * borderFade) / 100)}px, ${color1} ${dashLength + spacing}px),
        repeating-linear-gradient(${slanting + (diraction ? 0 : 180) }deg, ${color1}, ${color1} ${Math.round(dashLength * borderFade) / 100}px, ${color2} ${dashLength}px, ${color2} ${dashLength + (Math.round(spacing * borderFade) / 100)}px, ${color1} ${dashLength + spacing}px),
        repeating-linear-gradient(${slanting + (diraction ? 90 : 270)}deg, ${color1}, ${color1} ${Math.round(dashLength * borderFade) / 100}px, ${color2} ${dashLength}px, ${color2} ${dashLength + (Math.round(spacing * borderFade) / 100)}px, ${color1} ${dashLength + spacing}px)`;

    const borderLengthPx = Math.round((dashLength + spacing) / Math.sin((90 - Math.abs(slanting)) * Math.PI / 180) * 100) / 100;
    const borderLength = (animation > 0) ? `calc(100% + ${borderLengthPx}px)` : '100%';
    const backgroundSize = `${borderWidth}px ${borderLength}, ${borderLength} ${borderWidth}px, ${borderWidth}px ${borderLength} , ${borderLength} ${borderWidth}px`;
    const backgroundPosition = `0 0, 0 0, 100% 0, 0 100%`;

    resultDiv.style.backgroundImage = backgroundImage;
    resultDiv.style.backgroundSize = backgroundSize;
    resultDiv.style.backgroundPosition = backgroundPosition;

    const animationPropery = (animation > 0) ? `borderAnimation ${Math.round((1.1 - animation) * 10) / 10}s infinite linear${diraction ? ' reverse' : ''}` : 'unset';
    resultDiv.style.animation = animationPropery;

    let animationTxt = '';
    if (animation > 0) {
        document.documentElement.style.setProperty('--AnimationLength', `-${borderLengthPx}px`);

        animationTxt = `
                <span><b>animation:</b> ${animationPropery};</span>
            }<br>
            <br>
            @keyframes <b>borderAnimation</b> {
                <span>from { background-position:  0 0, -${borderLengthPx}px 0, 100% -${borderLengthPx}px, 0 100%; }</span>
                <span>to { background-position:  0 -${borderLengthPx}px, 0 0, 100% 0, -${borderLengthPx}px 100%; }</span>
        `;
    }

    resultDiv.style.padding = `calc(1em + ${borderWidth}px)`;
    
    resultDiv.innerHTML = `
        <code>
            .box {
                <span><b>background-image:</b> ${backgroundImage};</span>
                <span><b>background-size:</b> ${backgroundSize};</span>
                <span><b>background-position:</b> ${backgroundPosition};</span>
                <span><b>background-repeat:</b> no-repeat; </span>
                ${animationTxt}
            }
        </code>
    `;
}
              
            
!
999px

Console