// source http://jsbin.com/qituro

index.html

<style id="jsbin-css">
.myButton {
	background-color:#44c767;
	-moz-border-radius:28px;
	-webkit-border-radius:28px;
	border-radius:28px;
	border:1px solid #18ab29;
	display:inline-block;
	cursor:pointer;
	color:#ffffff;
	font-family:Arial;
	font-size:17px;
	padding:16px 31px;
	text-decoration:none;
	text-shadow:0px 1px 0px #2f6627;
}
.myButton:hover {
	background-color:#5cbf2a;
}
.myButton:active {
	position:relative;
	top:1px;
}
</style>
<a href="sms://5511223344" class="myButton">Enviar Mensaje</a>
<script id="jsbin-javascript">
.myButton {
	background-color:#44c767;
	-moz-border-radius:28px;
	-webkit-border-radius:28px;
	border-radius:28px;
	border:1px solid #18ab29;
	display:inline-block;
	cursor:pointer;
	color:#ffffff;
	font-family:Arial;
	font-size:17px;
	padding:16px 31px;
	text-decoration:none;
	text-shadow:0px 1px 0px #2f6627;
}
.myButton:hover {
	background-color:#5cbf2a;
}
.myButton:active {
	position:relative;
	top:1px;
}
</script>

<script id="jsbin-source-css" type="text/css">.myButton {
	background-color:#44c767;
	-moz-border-radius:28px;
	-webkit-border-radius:28px;
	border-radius:28px;
	border:1px solid #18ab29;
	display:inline-block;
	cursor:pointer;
	color:#ffffff;
	font-family:Arial;
	font-size:17px;
	padding:16px 31px;
	text-decoration:none;
	text-shadow:0px 1px 0px #2f6627;
}
.myButton:hover {
	background-color:#5cbf2a;
}
.myButton:active {
	position:relative;
	top:1px;
}</script>

<script id="jsbin-source-javascript" type="text/javascript">.myButton {
	background-color:#44c767;
	-moz-border-radius:28px;
	-webkit-border-radius:28px;
	border-radius:28px;
	border:1px solid #18ab29;
	display:inline-block;
	cursor:pointer;
	color:#ffffff;
	font-family:Arial;
	font-size:17px;
	padding:16px 31px;
	text-decoration:none;
	text-shadow:0px 1px 0px #2f6627;
}
.myButton:hover {
	background-color:#5cbf2a;
}
.myButton:active {
	position:relative;
	top:1px;
}</script>

jsbin.qituro.css

.myButton {
	background-color:#44c767;
	-moz-border-radius:28px;
	-webkit-border-radius:28px;
	border-radius:28px;
	border:1px solid #18ab29;
	display:inline-block;
	cursor:pointer;
	color:#ffffff;
	font-family:Arial;
	font-size:17px;
	padding:16px 31px;
	text-decoration:none;
	text-shadow:0px 1px 0px #2f6627;
}
.myButton:hover {
	background-color:#5cbf2a;
}
.myButton:active {
	position:relative;
	top:1px;
}

jsbin.qituro.js

.myButton {
	background-color:#44c767;
	-moz-border-radius:28px;
	-webkit-border-radius:28px;
	border-radius:28px;
	border:1px solid #18ab29;
	display:inline-block;
	cursor:pointer;
	color:#ffffff;
	font-family:Arial;
	font-size:17px;
	padding:16px 31px;
	text-decoration:none;
	text-shadow:0px 1px 0px #2f6627;
}
.myButton:hover {
	background-color:#5cbf2a;
}
.myButton:active {
	position:relative;
	top:1px;
}