Edit in JSFiddle

    <form class="search">
  <input class="searchTerm" placeholder="Enter your search term ..." /><input class="searchButton" type="submit" />
</form>
    <script src='http://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js'></script>
@import url(http://netdna.bootstrapcdn.com/font-awesome/3.2.1/css/font-awesome.css);
.search {
  width: 100%;
  position: relative;
}
.search:before {
  position: absolute;
  top: 0;
  right: 0;
  width: 40px;
  height: 40px;
  line-height: 40px;
  font-family: 'FontAwesome';
  content: '\f002';
  background: #8FC357;
  text-align: center;
  color: #fff;
  border-radius: 5px;
  -webkit-font-smoothing: subpixel-antialiased;
  font-smooth: always;
}

.searchTerm {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
  width: 100%;
  border: 5px solid #8FC357;
  padding: 5px;
  height: 40px;
  border-radius: 5px;
  outline: none;
}

.searchButton {
  position: absolute;
  top: 0;
  right: 0;
  width: 40px;
  height: 40px;
  opacity: 0;
  cursor: pointer;
}
$('.searchButton').on('click',function(){
  alert('You clicked search button');
});