可扩展纯css3圆形搜索框是一款适合移动和响应的设计。

效果非常酷,但是不支持低版本的IE浏览器哦.

css部分代码

input {
outline: none;
}
input[type=search] {
-webkit-appearance: textfield;
-webkit-box-sizing: content-box;
font-family: inherit;
font-size: 100%;
}
input::-webkit-search-decoration,
input::-webkit-search-cancel-button {
display: none; /* remove the search and cancel icon */
}

/* search input field */
input[type=search] {
background: #ededed url(images/search-icon.png) no-repeat 9px center;
border: solid 1px #ccc;
padding: 9px 10px 9px 32px;
width: 55px;

-webkit-border-radius: 10em;
-moz-border-radius: 10em;
border-radius: 10em;

-webkit-transition: all .5s;
-moz-transition: all .5s;
transition: all .5s;
}
input[type=search]:focus {
width: 130px;
background-color: #fff;
border-color: #6dcff6;

-webkit-box-shadow: 0 0 5px rgba(109,207,246,.5);
-moz-box-shadow: 0 0 5px rgba(109,207,246,.5);
box-shadow: 0 0 5px rgba(109,207,246,.5);
}

/* placeholder */
input:-moz-placeholder {
color: #999;
}
input::-webkit-input-placeholder {
color: #999;
}

/* demo B */
#demo-b input[type=search] {
width: 15px;
padding-left: 10px;
color: transparent;
cursor: pointer;
}
#demo-b input[type=search]:hover {
background-color: #fff;
}
#demo-b input[type=search]:focus {
width: 130px;
padding-left: 32px;
color: #000;
background-color: #fff;
cursor: auto;
}
#demo-b input:-moz-placeholder {
color: transparent;
}
#demo-b input::-webkit-input-placeholder {
color: transparent;
}

下载地址    演示地址