问题

我创建了一个完全由CSS完成的下拉菜单，使用了教程中介绍的绝对定位方法。 效果很好。 在Safari中，它运行缓慢，缓慢，并且链接间隔开。

该下拉菜单可在Safari以外的所有浏览器中完美运行。 为什么？

• Home

  • About Us
  • Contact Us
  • Managed Services

• Computer

  • Malware Removal
  • Diagnostic
  • Backup & Restore
  • Data Recovery
  • Phone Accessories

• Security

  • Surveillance
  • Security Systems

• Home Automation

  • HAI
  • RTI

• Home Audio / Video

  • TV Installation
  • Wall Mounting
  • Sound Systems
  • Home Theater
  • Munitio Earphones

的CSS

/* Header */

#nav {

margin-left: 9%;

list-style: none;

font-weight: bold;

margin-bottom: 10px;

margin-top: 40px; /* Clear floats */

float: left;

width: 90%; /* Bring the nav above everything else--uncomment if needed.

position: relative;

*/

z-index: 5;

}

#nav li {

float: left;

margin-right: 2%;

}

#nav a {

display: block;

padding: 5px;

color: black;

background: none;

text-decoration: none;

font-size: 14px;

-webkit-transition: color 0.2s, text-shadow 0.3s;

-moz-transition: color 0.2s, text-shadow 0.3s;

-o-transition: color 0.2s, text-shadow 0.3s;

-ms-transition: color 0.2s, text-shadow 0.3s;

transition: color 0.2s, text-shadow 0.3s;

}

#nav a:hover {

color: white;

background: none;

text-decoration: none;

text-shadow: 0px 0px 3px #000;

}

/*---DROPDOWN ---*/

#nav ul {

z-index: 5;

background: none; /* Adding a background makes the dropdown work properly in IE7+. Make this as close to your page's background as possible (i.e. white page == white background). */

background: rgba(255,255,255,0); /* But! Let's make the background fully transparent where we can, we don't actually want to see it if we can help it... */

list-style: none;

width: 0px;

overflow: hidden;

color:white;

left: -9999px; /* Hide off-screen when not needed (this is more accessible than display: none;

*/

-webkit-transition: color 0.2s, text-shadow 0.3s;

-moz-transition: color 0.2s, text-shadow 0.3s;

-o-transition: color 0.2s, text-shadow 0.3s;

-ms-transition: color 0.2s, text-shadow 0.3s;

transition: color 0.2s, text-shadow 0.3s;

}

#nav ul li {

padding-top: 1px; /* Introducing a padding between the li and the a give the illusion spaced items */

color:white;

float: none;

}

#nav ul a {

white-space: nowrap; /* Stop text wrapping and creating multi-line dropdown items */

}

#nav li:hover ul {

/* Display the dropdown on hover */

left: 0; /* Bring back on-screen when needed */

overflow: hidden;

width: 150px;

-webkit-transition: width 0.2s;

-moz-transition: width 0.2s;

-o-transition: width 0.2s;

-ms-transition: width 0.2s;

transition: width 0.2s;

}

#nav li:hover a {

/* These create persistent hover states, meaning the top-most link stays 'hovered' even when your cursor has moved down the list. */

background: none;

margin-right: -10px;

text-decoration: none;

-webkit-transition: margin-right 1s;

-moz-transition: margin-right 1s;

-o-transition: margin-right 1s;

-ms-transition: margin-right 1s;

transition: margin-right 1s;

}

#nav li:hover ul a {

/* The persistent hover state does however create a global style for links even before they're hovered. Here we undo these effects. */

text-decoration: none;

width: 120px;

}

#nav li:hover ul li a:hover {

/* Here we define the most explicit hover states--what happens when you hover each individual link. */

background: #333;

width: 150px;

}