input 默认值为灰色，输入时清楚默认值
<input value="please input your name" onFocus="if(value==defaultValue){value=‘‘;this.style.color=‘#000‘}" onBlur="if(!value){value=defaultValue; this.style.color=‘#999‘}" style="color:#999" ng-model="owner_name" id="owner" />
原文：http://www.cnblogs.com/juandx/p/5576347.html