如何使用Rails file_field拒绝.pdf文件

Question

我只想接受png，gif和jpeg所以我在file_field上有以下内容，但它仍然接受pdfs

json

Answer 1

告诉它这是一张图片。

<div id="bigcontainer">
   <div id="maincontainer">
      <div id="upcomingActivitiesTitle">Upcoming Activities</div>
      <div id="container">
         <div id="subcontainer">
            <br/>
            <br/> 
            <div id="patching">Unix Patching 2.0</div>
            <div id="patchingDesc"> 
               <b>The Unix Team will have a 5- hour regular maintenance on Sunday, 23 

April 2017 starting 08:00 AM ET. There will be no user disruption during this 

activity</b></div>
            <br/>
            <br/>
            <br/> 
            <div id="networkMaintenance">Network Maintenance</div>
            <div id="networkMaintenanceDesc"> 
               <b>The Unix Team will have a 5-hour regular maintenance on Sunday, 23 

April 2017 starting 08:00AM ET. There will be no user disruption during this 

activity.</b></div>
         </div>
      </div>
      <div id="clickMore">
         <a href="#">Click More</a></div>
   </div> 
   <a id="tutorialsa" href="#">
      <div id="tutorialVideos">&#160;</div></a><a id="calendara" href="#">
      <div id="calendar">&#160;</div></a>
   <div id="selfService"> 
      <br/> 
      <br/>
      <div id="titleSelfService">Self Service</div> 
      <br/>
      <div id="howto">
         <a id="howtoa" href="#">How To 
            <div id="imghowto">&#160;</div></a> </div>
      <div id="hpsm">
         <a id="hpsma" href="#">HPSM 
            <div id="imghpsm">&#160;</div></a> </div>
   </div>
</div>