JS 屏蔽F1~F12的快捷键

 

function window.onhelp(){return false} //屏蔽F1帮助 
/*keyCod从113-123分别禁用了F2-F12键,13禁用了回车键(Enter),8禁用了退格键(BackSpace)*/    
     
  document.onkeydown   =   function(){    
      if(window.event   &&   window.event.keyCode   ==   113)   {    
          window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   114)   {    
          window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   115)   {    
          window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   116)   {    
          window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   117)   {    
          window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   118)   {    
          window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   119)   {    
          window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   120)   {    
        window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   121)   {    
        window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   122)   {    
        window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   123)   {    
        window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   13)   {    
        window.event.keyCode   =   505;    
      }    
      if(window.event   &&   window.event.keyCode   ==   8)   {    
        alert(str+"\n请使用Del键进行字符的删除操作！");    
        window.event.returnValue=false;    
      }    
      if(window.event   &&   window.event.keyCode   ==   505){    
  　　alert(str)    
          window.event.returnValue=false;    
      }    
  }