Example 1

This is the first example of code that explains how to build a custom form widget.

Basic state

HTML

<div class="select">
  <span class="value">Cherry</span>
  <ul class="optList hidden">
    <li class="option">Cherry</li>
    <li class="option">Lemon</li>
    <li class="option">Banana</li>
    <li class="option">Strawberry</li>
    <li class="option">Apple</li>
  </ul>
</div>

CSS

/* --------------- */
/* Required Styles */
/* --------------- */

.select {
  position: relative;
  display : inline-block;
}

.select.active,
.select:focus {
  box-shadow: 0 0 3px 1px #227755;
  outline: none;
}

.select .optList {
  position: absolute;
  top     : 100%;
  left    : 0;
}

.select .optList.hidden {
  max-height: 0;
  visibility: hidden;
}

/* ------------ */
/* Fancy Styles */
/* ------------ */

.select {
  font-size   : 0.625em; /* 10px */
  font-family : Verdana, Arial, sans-serif;

  -moz-box-sizing : border-box;
  box-sizing : border-box;

  padding : 0.1em 2.5em 0.2em 0.5em; /* 1px 25px 2px 5px */
  width   : 10em; /* 100px */

  border        : 0.2em solid #000; /* 2px */
  border-radius : 0.4em; /* 4px */

  box-shadow : 0 0.1em 0.2em rgba(0,0,0,.45); /* 0 1px 2px */

  background : #F0F0F0;
  background : linear-gradient(0deg, #E3E3E3, #fcfcfc 50%, #f0f0f0);
}

.select .value {
  display  : inline-block;
  width    : 100%;
  overflow : hidden;

  white-space   : nowrap;
  text-overflow : ellipsis;
  vertical-align: top;
}

.select:after {
  content : "▼";
  position: absolute;
  z-index : 1;
  height  : 100%;
  width   : 2em; /* 20px */
  top     : 0;
  right   : 0;

  padding-top : .1em;

  -moz-box-sizing : border-box;
  box-sizing : border-box;

  text-align : center;

  border-left  : .2em solid #000;
  border-radius: 0 .1em .1em 0;

  background-color : #000;
  color : #FFF;
}

.select .optList {
  z-index : 2;

  list-style: none;
  margin : 0;
  padding: 0;

  background: #f0f0f0;
  border: .2em solid #000;
  border-top-width : .1em;
  border-radius: 0 0 .4em .4em;

  box-shadow: 0 .2em .4em rgba(0,0,0,.4);

  box-sizing : border-box;

  min-width : 100%;
  max-height: 10em; /* 100px */
  overflow-y: auto;
  overflow-x: hidden;
}

.select .option {
  padding: .2em .3em;
}

.select .highlight {
  background: #000;
  color: #FFFFFF;
}

Result for basic state

Active state

HTML

<div class="select active">
  <span class="value">Cherry</span>
  <ul class="optList hidden">
    <li class="option">Cherry</li>
    <li class="option">Lemon</li>
    <li class="option">Banana</li>
    <li class="option">Strawberry</li>
    <li class="option">Apple</li>
  </ul>
</div>

CSS

/* --------------- */
/* Required Styles */
/* --------------- */

.select {
  position: relative;
  display : inline-block;
}

.select.active,
.select:focus {
  box-shadow: 0 0 3px 1px #227755;
  outline: none;
}

.select .optList {
  position: absolute;
  top     : 100%;
  left    : 0;
}

.select .optList.hidden {
  max-height: 0;
  visibility: hidden;
}

/* ------------ */
/* Fancy Styles */
/* ------------ */

.select {
  font-size   : 0.625em; /* 10px */
  font-family : Verdana, Arial, sans-serif;

  box-sizing : border-box;

  padding : 0.1em 2.5em 0.2em 0.5em; /* 1px 25px 2px 5px */
  width   : 10em; /* 100px */

  border        : 0.2em solid #000; /* 2px */
  border-radius : 0.4em; /* 4px */

  box-shadow : 0 0.1em 0.2em rgba(0,0,0,.45); /* 0 1px 2px */

  background : #F0F0F0;
  background : linear-gradient(0deg, #E3E3E3, #fcfcfc 50%, #f0f0f0);
}

.select .value {
  display  : inline-block;
  width    : 100%;
  overflow : hidden;

  white-space   : nowrap;
  text-overflow : ellipsis;
  vertical-align: top;
}

.select:after {
  content : "▼";
  position: absolute;
  z-index : 1;
  height  : 100%;
  width   : 2em; /* 20px */
  top     : 0;
  right   : 0;

  padding-top : .1em;

  -moz-box-sizing : border-box;
  box-sizing : border-box;

  text-align : center;

  border-left  : .2em solid #000;
  border-radius: 0 .1em .1em 0;

  background-color : #000;
  color : #FFF;
}

.select .optList {
  z-index : 2;

  list-style: none;
  margin : 0;
  padding: 0;

  background: #f0f0f0;
  border: .2em solid #000;
  border-top-width : .1em;
  border-radius: 0 0 .4em .4em;

  box-shadow: 0 .2em .4em rgba(0,0,0,.4);

  box-sizing : border-box;

  min-width : 100%;
  max-height: 10em; /* 100px */
  overflow-y: auto;
  overflow-x: hidden;
}

.select .option {
  padding: .2em .3em;
}

.select .highlight {
  background: #000;
  color: #FFFFFF;
}

Result for active state

Open state

HTML

<div class="select active">
  <span class="value">Cherry</span>
  <ul class="optList">
    <li class="option highlight">Cherry</li>
    <li class="option">Lemon</li>
    <li class="option">Banana</li>
    <li class="option">Strawberry</li>
    <li class="option">Apple</li>
  </ul>
</div>

CSS

/* --------------- */
/* Required Styles */
/* --------------- */

.select {
  position: relative;
  display : inline-block;
}

.select.active,
.select:focus {
  box-shadow: 0 0 3px 1px #227755;
  outline: none;
}

.select .optList {
  position: absolute;
  top     : 100%;
  left    : 0;
}

.select .optList.hidden {
  max-height: 0;
  visibility: hidden;
}

/* ------------ */
/* Fancy Styles */
/* ------------ */

.select {
  font-size   : 0.625em; /* 10px */
  font-family : Verdana, Arial, sans-serif;

  -moz-box-sizing : border-box;
  box-sizing : border-box;

  padding : 0.1em 2.5em 0.2em 0.5em; /* 1px 25px 2px 5px */
  width   : 10em; /* 100px */

  border        : 0.2em solid #000; /* 2px */
  border-radius : 0.4em; /* 4px */

  box-shadow : 0 0.1em 0.2em rgba(0, 0, 0, .45); /* 0 1px 2px */

  background : #F0F0F0;
  background : linear-gradient(0deg, #E3E3E3, #fcfcfc 50%, #f0f0f0);
}

.select .value {
  display  : inline-block;
  width    : 100%;
  overflow : hidden;

  white-space   : nowrap;
  text-overflow : ellipsis;
  vertical-align: top;
}

.select:after {
  content : "▼";
  position: absolute;
  z-index : 1;
  height  : 100%;
  width   : 2em; /* 20px */
  top     : 0;
  right   : 0;

  padding-top : .1em;

  box-sizing : border-box;

  text-align : center;

  border-left  : .2em solid #000;
  border-radius: 0 .1em .1em 0;

  background-color : #000;
  color : #FFF;
}

.select .optList {
  z-index : 2;

  list-style: none;
  margin : 0;
  padding: 0;

  background: #f0f0f0;
  border: .2em solid #000;
  border-top-width : .1em;
  border-radius: 0 0 .4em .4em;

  box-shadow: 0 .2em .4em rgba(0,0,0,.4);

  -moz-box-sizing : border-box;
  box-sizing : border-box;

  min-width : 100%;
  max-height: 10em; /* 100px */
  overflow-y: auto;
  overflow-x: hidden;
}

.select .option {
  padding: .2em .3em;
}

.select .highlight {
  background: #000;
  color: #FFF;
}

Result for open state