You're trying to apply HTML elements in an element attribute which obviously won't work. One of the challenges in styling buttons is that by default they are inline elements, so there will be oddities when you style the size of the type inside the buttons; be sure to set the display to block (and sometimes remove the border, as below.)
The tested code below will render as a round cornered gradient submit button with mouseover effects, where you can access the button text and style it appropriately.
In exchange, please don't use
"Click Here [w3.org]" :-)
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Untitled</title>
<style type="text/css">
#mybutton {
display: block;
width: 6em;
height: 2em;
border: none;
padding:0;
text-align:center;
font-size: 1.5em;
line-height:1.5em;
color:#fff;
cursor:pointer;
-webkit-border-radius:6px;
-moz-border-radius:6px;
-ms-border-radius:6px;
-o-border-radius:6px;
border-radius:6px;
background-image: linear-gradient(bottom, rgb(58,83,186) 12%, rgb(127,187,240) 49%);
background-image: -o-linear-gradient(bottom, rgb(58,83,186) 12%, rgb(127,187,240) 49%);
background-image: -moz-linear-gradient(bottom, rgb(58,83,186) 12%, rgb(127,187,240) 49%);
background-image: -webkit-linear-gradient(bottom, rgb(58,83,186) 12%, rgb(127,187,240) 49%);
background-image: -ms-linear-gradient(bottom, rgb(58,83,186) 12%, rgb(127,187,240) 49%);
background-image: -webkit-gradient(
linear,
left bottom,
left top,
color-stop(0.12, rgb(58,83,186)),
color-stop(0.49, rgb(127,187,240))
);
}
#mybutton:hover {
color: #000080;
background-image: linear-gradient(bottom, rgb(120,146,250) 12%, rgb(182,244,252) 49%);
background-image: -o-linear-gradient(bottom, rgb(120,146,250) 12%, rgb(182,244,252) 49%);
background-image: -moz-linear-gradient(bottom, rgb(120,146,250) 12%, rgb(182,244,252) 49%);
background-image: -webkit-linear-gradient(bottom, rgb(120,146,250) 12%, rgb(182,244,252) 49%);
background-image: -ms-linear-gradient(bottom, rgb(120,146,250) 12%, rgb(182,244,252) 49%);
background-image: -webkit-gradient(
linear,
left bottom,
left top,
color-stop(0.12, rgb(120,146,250)),
color-stop(0.49, rgb(182,244,252))
);
}
form { width: 6em; margin:auto; }
</style>
</head>
<body>
<form action="">
<p><input type="submit" id="mybutton" value="submit"></p>
</body>
</html>