1 ::-moz-placeholder{color:#999;}                 //Firefox
2 ::-webkit-input-placeholder{color:#999;}      //chrome和Safari
3 :-ms-input-placeholder{color:#999;}            //IE10

1 <div id="inputPlaceholder">
2     <input type="text" value="" id="inputBox" onfocus="OnFocus()" onblur="OnBlur()"  autocomplete="off">
3     <label for="inputBox" id="labelPlaceholder">请输入号码</label>
4 </div>

 1 function OnFocus () {
 2         document.getElementById("labelPlaceholder").style.display="none";             //当input获取焦点时，label隐藏
 3     }
 4 function OnBlur () {
 5         if (document.getElementById("inputBox").value=="") {
 6             document.getElementById("labelPlaceholder").style.display="block";        //当input失去焦点时，如果input框中有内容则label隐藏，如果没有内容则label显示
 7         } else{
 8             document.getElementById("labelPlaceholder").style.display="none";
 9         };
10
11     }

 1 #inputPlaceholder{
 2         width: 100%;
 3         height: auto;
 4         position: relative;
 5     }
 6 #inputBox{
 7         width: 100%;
 8         height: 30px;
 9         line-height:30px;
10         border:1px #DBEAF9 solid;
11         border-radius:5px;
12         background-color:#fff;
13         text-align:center;
14         font-size: 14px;
15         padding: 0;
16         margin: 0;
17         color:#333;
18     }
19 #labelPlaceholder{
20         width: 100%;
21         height: 32px;
22         line-height: 32px;
23         color:#999;
24         font-size: 14px;
25         position: absolute;
26         top: 0;
27         left: 0;
28         padding: 0;
29         margin: 0;
30         text-align:center;
31     }
32 ::-moz-placeholder{color:#999;}
33 ::-webkit-input-placeholder{color:#999;}
34 :-ms-input-placeholder{color:#999;}