Answer by user1432181 for Unicode character for "X" cancel / close?

Using modern browsers you can rotate a + sign:

.popupClose:before {    content:'+';}.popupClose {    position:relative;    float:right;    right:10px;    top:0px;    padding:2px;    cursor:pointer;    margin:2px;    color:grey;    font-size:32pt;    transform:rotate(45deg);}

then simply place the following html where you need:

<span class='popupClose'></span>