JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdn.jquerytools.org/1.2.7/full/jquery.tools.min.js"></script>
<img class="plus" src="http://cdn1.iconfinder.com/data/icons/icojoy/noshadow/standart/png/24x24/001_01.png" rel="#form" data-date="2012-09-01">
<img src="http://cdn1.iconfinder.com/data/icons/icojoy/noshadow/standart/png/24x24/001_01.png" class="plus" rel="#form" data-date="2012-09-02">
<img src="http://cdn1.iconfinder.com/data/icons/icojoy/noshadow/standart/png/24x24/001_01.png" class="plus" rel="#form" data-date="2012-09-03">

<div class="simple_overlay" id="form">
    <h1 id="formHead"></h1>
    <input id="formDate" name="date">
</div>

CSS

.simple_overlay {
 
    /* must be initially hidden */
    display:none;
 
    /* place overlay on top of other elements */
    z-index:10000;
 
    /* styling */
    background-color:#333;
 
    width:275px;
    min-height:200px;
    border:1px solid #666;
    color:white;
 
    /* CSS3 styling for latest browsers */
    -moz-box-shadow:0 0 90px 5px #000;
    -webkit-box-shadow: 0 0 90px #000;
}
 
/* close button positioned on upper right corner */
.simple_overlay .close {
    background:red;
    position:absolute;
    right:-15px;
    top:-15px;
    cursor:pointer;
    height:35px;
    width:35px;
}

JavaScript

jQuery(function($) {
  $('.plus').click(function() {
    var date=$(this).attr('data-date');
    $('#formHead').text('Eintrag für '+date);
    $('#formDate').val(date);
  }).overlay();
});