css+div 问题 （关于绝对定位和相对定位的问题）

...火狐狸```

请问一下，为什么以下的代码中红色的地方要用相对定位 蓝色的地方要用绝对定位呢，相对定位不是针对整个页面来讲的吗

body{
    background:url(body_bg.jpg) repeat-y center;    /* 页面的两条竖线 */
    background-color:#000000;
    margin: 0px;
    padding:0px;
    text-align:center;
}
#container{                                            /* 固定宽度且居中的版式 */
    position:relative;
    margin:0px auto 0px auto;
    width:800px;
    text-align:left;
    background:url(container_bg.jpg) no-repeat bottom right;
    /* 底部右侧的背景图片 */
}
#globallink{
    width:800px;
    height:430px;
    margin:0px;
    background-image:url(banner.jpg);
    background-repeat:no-repeat;
    font-size:12px;
    padding-bottom:0px;
}
#globallink ul{
    list-style-type:none;
    position:absolute;                /* 绝对定位 */
    display:block;
    left:761px;
    top:58px;
    padding:0px; margin:0px;
}
#globallink li{
    text-align:center;
    padding-top:18px;
    width:30px;
}
#globallink a:link, #globallink a:visited{
    color:#FFFFFF;
    text-decoration:none;
}
#globallink a:hover{
    color:#000000;
    text-decoration:none;
}

#parameter{
    position:relative;
    float:left;                                    /* 左浮动 */
    font-size:12px;
    width:190px;                                /* 固定宽度 */
    padding:0px 6px 20px 0px;
    margin-top:-88px;                            /* 向左移动出去 */
    color:#bb9d80;
    background:url(parabottom.jpg) no-repeat bottom;    /* 下部圆角 */
    background-color:#3e3226;
}
#parameter h3 span{
    display:none;
}
#parameter h3{
    height:28px; width:190px;
    padding:0px; margin:0px;
}
#parameter br{
    clear:both;
    display:none;
}
#parameter div{
    margin-bottom:22px;
}
#parameter a:link, #parameter a:visited{
    color:#c2b2a2;
    text-decoration:none;
}
#parameter a:hover{
    color:#FFFF00;
    text-decoration:none;
}
#parameter a.author1:link{
    color:#d8924d;
    font-size:12px;
    text-decoration:none;
}
#parameter a.author1:visited{
    color:#b37941;
    font-size:12px;
    text-decoration:none;
}
#parameter a.author1:hover{
    color:#74b8ff;
    font-size:12px;
    text-decoration:none;
}
#lstatistics h3{
    height:0px;
}
#lhotblog h3{
    background:url(lhotblog.jpg) no-repeat;
}
#lrecent h3{
    background:url(lrecent.jpg) no-repeat;
}
#lapply h3{
    background:url(lapply.jpg) no-repeat;
}
#lhotblog span a, #lrecent span a, #lapply span a{
    float:right;
    text-align:right;
    padding-top:8px;
    padding-right:8px;
    margin-bottom:5px;
}
#lstatistics, #lhotblog, #lrecent, #lapply{
    position:relative;
    clear:both;
}
#lstatistics ul, #lhotblog ul, #lrecent ul, #lapply ul{
    list-style-type:none;
    padding-top:12px;
    padding-left:10px;
    padding-right:5px;
    margin:0px;
}
#lstatistics li{
    text-align:left;
    padding-left:18px;
    line-height:18px;
    background:url(arrow1.gif) no-repeat 7px 5px;
}
#lhotblog li{
    text-align:left;
    padding-left:16px;
    line-height:17px;
    background:url(arrow2.gif) no-repeat 7px 6px;
}
#lrecent li, #lapply li{
    text-align:left;
    padding-left:16px;
    line-height:17px;
    background:url(arrow3.gif) no-repeat 7px 6px;
}

#mainsupport{
    float:left;
    position:relative;
    color:#c86615;
    font-size:12px;
    margin:10px 20px 0px 20px;
    padding-left:12px;
    width:510px;
}
#mainsupport h3 span,#mainsupport h3{
    display:none;
}
#mainsupport li a:link, #mainsupport li a:visited{
    color:#ddaf80;
    font-size:12px;
    text-decoration:none;
}
#mainsupport li a:hover{
    color:#BBAA00;
    font-size:12px;
    text-decoration:none;
}
#mainsupport li a.author2:link{
    color:#cb9a32;
    font-size:12px;
    text-decoration:none;
}
#mainsupport li a.author2:visited{
    color:#cb9a32;
    font-size:12px;
    text-decoration:none;
}
#mainsupport li a.author2:hover{
    color:#8a8a8a;
    font-size:12px;
    text-decoration:underline;
}
#recommendblog br, #currenttime br, #blogsearch br,#logoin br{
    display:none;
    clear:both;
}
#recommendblog{
    height:140px;
    background:url(recommendblog.jpg) no-repeat;
    margin:0px;
    padding-top:15px;
    padding-bottom:0px;
    padding-left:125px;
}
#recommendblog ul{
    margin-top:8px;
    margin-left:0px;
    margin-bottom:0px;
    padding-top:10px;
    padding-left:10px;
    list-style-type:none;
}
#recommendblog li{
    padding-left:20px;
    line-height:19px;
    background:url(arrow4.gif) no-repeat 5px 6px;
}
#recommendblog span a:link, #recommendblog span a:visited{
    color:#c87e2e;
    text-decoration:none;
    padding-left:10px;
    font-weight:bold;
}
#recommendblog span a:hover{
    color:#CCCC00;
    text-decoration:underline;
    padding-left:10px;
    font-weight:bold;
}
#recommendblog span a.author2{
    font-weight:lighter;
}
#recommendblog span a.author2:link{
    color:#d5503f;
    text-decoration:none;
}
#recommendblog span a.author2:visited{
    color:#d5503f;
    text-decoration:none;
    font-weight:lighter;
}
#recommendblog span a.author2:hover{
    color:#BBCC44;
    text-decoration:underline;
    font-weight:lighter;
}
#currenttime{
    height:50px;
    margin-top:12px;
    padding-top:16px;
    padding-left:5px;
    background:url(currenttime.jpg) no-repeat;
}
#currenttime p.p1{
    color:#93c8ff;
    margin:0px;
    padding-left:15px;
    padding-right:10px;
    display:inline;
}
#currenttime p.p2{
    color:#57b6ff;
    margin:0px;
    padding-left:0px;
    padding-right:0px;
    display:inline;
}
#currenttime p a.astro:link, #currenttime p a.astro:visited{
    color:#76c7ff;
    font-size:12px;
    text-decoration:none;
}
#currenttime p a.astro:hover{
    color:#DDDD00;
    font-size:12px;
    text-decoration:underline;
}
#currenttime ul{
    padding-left:10px;
    padding-right:8px;
    text-align:center;
    margin:0px;
    list-style-type:none;
}
#currenttime li{
    float:left;
    width:17px;
    line-height:20px;
}
form{
    padding:0px;
    margin:0px;
}
input{
    margin:0px; padding:0px;
}
#blogsearch{
    margin:0px;
    height:30px;
}
#blogsearch ul{
    margin:0px;
    padding-left:10px;
    padding-top:4px;
    list-style-type:none;
    text-align:left;
}
#blogsearch li{
    float:left;
    line-height:22px;
}
#blogsearch li#sear1 input{
    background-color:#000000;
    border:1px solid #c86615;
    color:#c86615;
    font-size:12px;
    height:15px;
    padding:0px;
    margin-right:8px;
}
#blogsearch #sear3 input,#blogsearch #sear4 input,#blogsearch #sear5 input{
    margin-left:5px;
}
#blogsearch #sear6 input{
    background-color:#000000;
    border:1px solid #c86615;
    color:#c86615;
    font-size:12px;
    height:17px;
    padding:0px;
    margin-left:8px;
    margin-top:2px;
    margin-bottom:0px;
}
#logoin{
    margin:0px;
    height:65px;
    background:url(manyboard.jpg) no-repeat;
}
#logoin ul#per{
    margin:0px;
    padding-left:15px;
    padding-top:15px;
    list-style-type:none;
    text-align:left;
}
#logoin ul#per li{
    padding-left:20px;
    line-height:20px;
    margin:0px;
    background:url(arrow5.gif) no-repeat 6px 5px;
}
#logoin #per input{
    background-color:#000000;
    border:1px solid #c86615;
    color:#c86615;
    font-size:12px;
    height:15px;
    padding:0px;
}
#logoin #per1 input.textinput1,#logoin #per2 input.textinput2{
    background-color:#000000;
    border:1px solid #c86615;
    color:#c86615;
    font-size:12px;
    height:14px;
    padding:0px;
    width:120px;
    FONT-FAMILY: "Tahoma","SimSun","Arial", "Helvetica", "sans-serif";
}
#recommendart br, #newnode br{
    clear:both;
    display:none;
}
#recommendart{
    background:url(recommendart.jpg) no-repeat;
    padding:0px;
    margin-top:10px;
}
#recommendart ul{
    list-style-type:none;
    padding-top:75px;
    padding-bottom:0px;
    padding-left:5px;
    padding-right:5px;
    margin:0px;
}
#recommendart li{
    line-height:18px;
    padding-left:15px;
    padding-right:0px;
    background:url(arrow6.gif) no-repeat 0px 5px;
}
#newnode ul{
    padding-left:73px;
    padding-right:5px;
    padding-bottom:0px;
    padding-top:5px;
    text-align:left;
    margin:0px;
    list-style-type:none;
}
#newnode li{
    line-height:18px;
    padding-left:15px;   
    background:url(arrow6.gif) no-repeat 0px 5px;
}
#newnode{
    background:url(newnode.jpg) no-repeat;
    padding:0px;
    margin-top:15px; margin-bottom:20px;
}

#footer{
    position:relative;
    clear:both;
    background:url(footer_bg.jpg) no-repeat;
    font-size:12px;
    height:44px;
    text-align:center;
    color:#C2C299;
    margin:0px;
    padding-top:16px;
}
#footer p{
    margin:0px;
    padding:0px;
    line-height:20px;
}
#footer a:link{
    color:#D3D388;
    font-size:12px;
    text-decoration:none;
}
#footer a:visited{
    color:#D3D388;
    font-size:12px;
    text-decoration:none;
}
#footer a:hover{
    color:#222222;
    font-size:12px;
    text-decoration:none;