//Create an array 
var allPageTags = new Array(); 

function hidebox2(theClass) {
//Populate the array with all the page tags
var allPageTags=document.getElementsByTagName("*");
//Cycle through the tags using a for loop
for (i=0; i<allPageTags.length; i++) {
//Pick out the tags with our class name
if (allPageTags[i].className==theClass) {
//Manipulate this in whatever way you want
 document.getElementById("login").style.display="none";
}
}
}