Partage d'exemples de code HTML5/CSS3 pour implémenter un magnifique formulaire d'inscription et de connexion étape par étape

<form id="msform">
    <!-- progressbar -->
    <ul id="progressbar">
        <li>Account Setup</li>
        <li>Social Profiles</li>
        <li>Personal Details</li>
    </ul>
    <!-- fieldsets -->
    <fieldset>
        <h2>Create your account</h2>
        <h3>This is step 1</h3>
        <input type="text" name="email" placeholder="Email" />
        <input type="password" name="pass" placeholder="Password" />
        <input type="password" name="cpass" placeholder="Confirm Password" />
        <input type="button" name="next" value="Next" />
    </fieldset>
    <fieldset>
        <h2>Social Profiles</h2>
        <h3>Your presence on the social network</h3>
        <input type="text" name="twitter" placeholder="Twitter" />
        <input type="text" name="facebook" placeholder="Facebook" />
        <input type="text" name="gplus" placeholder="Google Plus" />
        <input type="button" name="previous" value="Previous" />
        <input type="button" name="next" value="Next" />
    </fieldset>
    <fieldset>
        <h2>Personal Details</h2>
        <h3>We will never sell it</h3>
        <input type="text" name="fname" placeholder="First Name" />
        <input type="text" name="lname" placeholder="Last Name" />
        <input type="text" name="phone" placeholder="Phone" />
        <textarea name="address" placeholder="Address"></textarea>
        <input type="button" name="previous" value="Previous" />
        <input type="submit" name="submit" value="Submit" />
    </fieldset></form>

/*form styles*/#msform {
    width: 400px;
    margin: 50px auto;
    text-align: center;
    position: relative;
}#msform fieldset {
    background: white;
    border: 0 none;
    border-radius: 3px;
    box-shadow: 0 0 15px 1px rgba(0, 0, 0, 0.4);
    padding: 20px 30px;

    box-sizing: border-box;
    width: 80%;
    margin: 0 10%;    /*stacking fieldsets above each other*/
    position: absolute;
}/*Hide all except first fieldset*/#msform fieldset:not(:first-of-type) {
    display: none;
}/*inputs*/#msform input, #msform textarea {
    padding: 15px;
    border: 1px solid #ccc;
    border-radius: 3px;
    margin-bottom: 10px;
    width: 100%;
    box-sizing: border-box;
    font-family: montserrat;
    color: #2C3E50;
    font-size: 13px;
}/*buttons*/#msform .action-button {
    width: 100px;
    background: #27AE60;
    font-weight: bold;
    color: white;
    border: 0 none;
    border-radius: 1px;
    cursor: pointer;
    padding: 10px 5px;
    margin: 10px 5px;
}#msform .action-button:hover, #msform .action-button:focus {
    box-shadow: 0 0 0 2px white, 0 0 0 3px #27AE60;
}/*headings*/.fs-title {
    font-size: 15px;
    text-transform: uppercase;
    color: #2C3E50;
    margin-bottom: 10px;
}.fs-subtitle {
    font-weight: normal;
    font-size: 13px;
    color: #666;
    margin-bottom: 20px;
}/*progressbar*/#progressbar {
    margin-bottom: 30px;
    overflow: hidden;    /*CSS counters to number the steps*/
    counter-reset: step;
}#progressbar li {
    list-style-type: none;
    color: white;
    text-transform: uppercase;
    font-size: 9px;
    width: 33.33%;
    float: left;
    position: relative;
}#progressbar li:before {
    content: counter(step);
    counter-increment: step;
    width: 20px;
    line-height: 20px;
    display: block;
    font-size: 10px;
    color: #333;
    background: white;
    border-radius: 3px;
    margin: 0 auto 5px auto;
}/*progressbar connectors*/#progressbar li:after {
    content: '';
    width: 100%;
    height: 2px;
    background: white;
    position: absolute;
    left: -50%;
    top: 9px;
    z-index: -1; 
    /*put it behind the numbers*/}
    #progressbar li:first-child:after {    
    /*connector not needed before the first step*/
    content: none; 
}
/*marking active/completed steps green*/
/*The number of the step and the connector before it = green*/
#progressbar li.active:before,  
#progressbar li.active:after{
    background: #27AE60;
    color: white;
}

var current_fs, next_fs, previous_fs; //fieldsets
var left, opacity, scale; //fieldset properties which we will animate
var animating; //flag to prevent quick multi-click glitches

$(".next").click(function(){
    if(animating) return false;
    animating = true;

    current_fs = $(this).parent();
    next_fs = $(this).parent().next();

    //activate next step on progressbar using the index of next_fs
    $("#progressbar li").eq($("fieldset").index(next_fs)).addClass("active");

    //show the next fieldset
    next_fs.show(); 
    //hide the current fieldset with style
    current_fs.animate({opacity: 0}, {
        step: function(now, mx) {
            //as the opacity of current_fs reduces to 0 - stored in "now"
            //1. scale current_fs down to 80%
            scale = 1 - (1 - now) * 0.2;
            //2. bring next_fs from the right(50%)
            left = (now * 50)+"%";
            //3. increase opacity of next_fs to 1 as it moves in
            opacity = 1 - now;
            current_fs.css({'transform': 'scale('+scale+')'});
            next_fs.css({'left': left, 'opacity': opacity});
        }, 
        duration: 800, 
        complete: function(){
            current_fs.hide();
            animating = false;
        }, 
        //this comes from the custom easing plugin
        easing: 'easeInOutBack'
    });
});

$(".previous").click(function(){
    if(animating) return false;
    animating = true;

    current_fs = $(this).parent();
    previous_fs = $(this).parent().prev();

    //de-activate current step on progressbar
    $("#progressbar li").eq($("fieldset").index(current_fs)).removeClass("active");

    //show the previous fieldset
    previous_fs.show(); 
    //hide the current fieldset with style
    current_fs.animate({opacity: 0}, {
        step: function(now, mx) {
            //as the opacity of current_fs reduces to 0 - stored in "now"
            //1. scale previous_fs from 80% to 100%
            scale = 0.8 + (1 - now) * 0.2;
            //2. take current_fs to the right(50%) - from 0%
            left = ((1-now) * 50)+"%";
            //3. increase opacity of previous_fs to 1 as it moves in
            opacity = 1 - now;
            current_fs.css({'left': left});
            previous_fs.css({'transform': 'scale('+scale+')', 'opacity': opacity});
        }, 
        duration: 800, 
        complete: function(){
            current_fs.hide();
            animating = false;
        }, 
        //this comes from the custom easing plugin
        easing: 'easeInOutBack'
    });
});

$(".submit").click(function(){
    return false;
})