BaseUrl simulation where "admin" is your first constant part

baseurl.js

var baseUrl = function(){
    // Calculate base url by filtering on the parts
    var parts = location.pathname.split('/'),
    base = '',
    i, 
    max;
    for (i = 0, max = parts.length; i < max; i++) {
        if(parts[i] === 'admin'){
            break;
        } else if(parts[i] === ''){
            continue;
        } else {
            base += '/' + parts[i];
        }
    }
    // Redefines the variable so it never has to get the base url again
    baseUrl = function(){
        return base;
    }
    return baseUrl();
}