设定属性rel为external与internal的不同

在网上看了一下js代码感觉有点用，就转过来，也算是俺的一点小练习。

<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >

< html  xmlns ="http://www.w3.org/1999/xhtml"  xml:lang ="en"  lang ="en" >
< head >
   < title ></ title >
   < style  type ="text/css" >
  #search {
    border : 1px solid #ccc ;
    color : #999 ;
   }

   </ style >
   < script  type ="text/javascript" >
   <!--
     function  addEvent(elm, evType, fn, useCapture)
         //  addEvent and removeEvent
         //  cross-browser event handling for IE5+,  NS6 and Mozilla
         //  By Scott Andrew
    {
           if  (elm.addEventListener){
            elm.addEventListener(evType, fn, useCapture);
             return   true ;
          }  else   if  (elm.attachEvent){
             var  r  =  elm.attachEvent( " on " + evType, fn);
             return  r;
          }  else  {
            alert( " Handler could not be removed " );
          }
    }

     function  externalLinks(){        // 设定属性rel为external的连接在新页面打开
         if ( ! document.getElementsByTagName)  return  ;
         var  anchors = document.getElementsByTagName( " a " );
         for ( var  i = 0 ;i < anchors.length;i ++ ){
            anchor = anchors[i];
             if (anchor.getAttribute( " href " ) && anchor.getAttribute( " rel " ) == " external " ){
                anchor.setAttribute( " target " , " _blank " );
            }
        }
    }

     function  onSearchFocus(){            // 搜索框获取焦点时
         var  search = document.getElementById( " search " );
         if (search.value == " 请输入关键字 " ){     // 如果输入框内容是“请输入关键字”，则清空内容，并设顶文字颜色为黑色
            search.value = "" ;
            search.style.color = " #000 "
        }
    }
     function  onSearchBlur(){             // 搜索框失去焦点时
         var  search = document.getElementById( " search " );
         if (search.value == "" ){                // 如果输入框内容为空，则设定文字颜色为灰色，内容为“请输入关键子”
            search.style.color = " #999 " ;
            search.value = " 请输入关键字 "
        }
    }
    addEvent(window, " load " ,externalLinks)
   -->
   </ script >
</ head >

< body >
< p >
[External links] < br  />
< a  href ="http://www.qq.com"  rel ="external" > QQ.com </ a >< br  />
< a  href ="http://www.163.com"  rel ="external" > 163.com </ a >< br  />
</ p >
< p >
[internal Links] < br  />
< a  href ="http://www.blueidea.com"  rel ="internal" > BlueIdea.com </ a >< br  />
< a  href ="http://www.51js.com"  rel ="internal" > 51Js.com </ a >< br  />
</ p >

< p >
[Input Test] < br  />
< input  type ="text"  id ="search"  value ="请输入关键字"  size ="20"  onFocus ="onSearchFocus()"  onblur ="onSearchBlur()"   />
</ p >
</ body >
</ html >

from index：http://www.cnitblog.com/yemoo/archive/2006/06/25/12827.html