jquery - css position an absolute div in relative with a slideable menu -

i not familiar css. need this, have setup fiddle displaying problem,

http://jsfiddle.net/naini/mbmq3/6/

.contentback{        width : 300px;     border : solid 30px;     position :absolute;     top :10; }  .masterdiv{     background-color: grey;     border: solid 1px;     width: 80%;     height:400px;     margin-top: 60px;     text-align: center;     padding : 10px;     position : relative; } 

i want contentback(thick black border) div inside of master div(grey background).

i dont want contentback relative because want menu overlap contentback instead of pushing right when menu appeared.

is there other solution on this?

p/s : should copy , paste whole jsfiddle thing question?

is closer looking ? http://jsfiddle.net/mbmq3/8/ or http://jsfiddle.net/mbmq3/10/ ? no height .masterdiv , .contentback kept in flow.

.masterdiv{     background-color: grey;     border: solid 1px;     width: 80%;     margin-top: 60px;     text-align: center;     padding : 10px;     position : relative; } .menudiv{     position: absolute;     z-index: 100;     background-color: white;     border: solid 1px;     width: 200px;     height: 300px;     float: left; } .menudiv li{     text-decoration: none; } .menubutton{     margin-top :-40px;     position: relative;     z-index: 100;     width : 100px;     height : 40px;     float: left;     writing-mode:tb-rl;     -webkit-transform:rotate(90deg);     -moz-transform:rotate(90deg);     -o-transform: rotate(90deg);      -moz-transform-origin :bottom left;     -o-transform-origin :bottom left;     -webkit-transform-origin :bottom left;  } .contentback{        width : 300px;     border : solid 30px;     position :;  } .contentbackpadding{     padding-left: 50px;  }