input标签type属性，默认的字体颜色为灰色，当输入字时，字体为黑色

<div class="frame">
    <h3 class="text text-site">siteName：</h3>
    <input type="text" name="" class="input" style="color:gray" value="请输入网站名称" onfocus="if(this.value==‘请输入网站名称‘){this.value=‘‘};this.style.color=‘black‘;" onblur="if(this.value==‘‘||this.value==‘请输入网站名称‘){this.value=‘请输入网站名称‘;this.style.color=‘gray‘;}" />
</div>

<div class="frame">
    <h3 class="text text-site">siteUrl：</h3>
    <input type="text" name="" class="input" style="color:gray" value="请输入网站地址" onfocus="if(this.value==‘请输入网站地址‘){this.value=‘‘};this.style.color=‘black‘;" onblur="if(this.value==‘‘||this.value==‘请输入网站地址‘){this.value=‘请输入网站地址‘;this.style.color=‘gray‘;}"/>
</div>

<input type="text" name="first_name" placeholder="请输入文本..." />

/* all */
::-webkit-input-placeholder { color:#f00; }
::-moz-placeholder { color:#f00; } /* firefox 19+ */
:-ms-input-placeholder { color:#f00; } /* ie */
input:-moz-placeholder { color:#f00; }

/* individual: webkit */
#field2::-webkit-input-placeholder { color:#00f; }
#field3::-webkit-input-placeholder { color:#090; background:lightgreen; text-transform:uppercase; }
#field4::-webkit-input-placeholder { font-style:italic; text-decoration:overline; letter-spacing:3px; color:#999; }

/* individual: mozilla */
#field2::-moz-placeholder { color:#00f; }
#field3::-moz-placeholder { color:#090; background:lightgreen; text-transform:uppercase; }
#field4::-moz-placeholder { font-style:italic; text-decoration:overline; letter-spacing:3px; color:#999; }