Try this:
<!DOCTYPE html>
<html>
<script language="javascript" type="text/javascript">
function buttonClick(){
var url = document.getElementById("inputURL").value;
window.location = url;
}
</script>
<body>
URL: <input type="text" id="inputURL" name="inputURL" value=""><br>
<input type="button" value="click" OnClick="buttonClick()"/>
</form>
</body>
</html>