Input 박스에 포커스 되었을때 스타일 변경

<style>
/* 포커스 했을때 input 스타일 변경  */
.input3 {
        color: #333333;
        background-color: #FFFFFF;
        border-bottom-width: 1px;
        border: 1px silver solid;
        height: 18;
        font-size:9pt;
}
.text_focus{
        background-color: #F3F3F3;
        border: 1px solid #3485D7;
        font-weight:bold;
}

.text_blur{
        background-color: white;
        border: 1px solid silver;
        font-weight:none;
}
< /style>
< input type=text name=word class=input3 style="width:175px;height:18px" onfocus="this.className='text_focus'" onblur="this.className='text_blur'">