Fixes a div and unfixes when the footer comes in.

Fixed div, hug footer

        var FixedScroll = function(options) { 
           // Make sure FixedScroll is being used as a constructor no matter what.
                if(!this || !(this instanceof FixedScroll)) {
                    return new FixedScroll(options);
                }
                this.fixedDiv = $('#iframe p');//div to be fixed
                this.fixedParent = this.fixedDiv.parent(); //container div of fixed div
                this.footer = $('.main_footer');// div to unfix at
                this.containerStart, this.footerStart;
                this.containerOffset = 210; //space from top of viewport to become fixed
                this.fixed,this.hugged; //booleans for logic switching
                this.init();
        }                
                        
        FixedScroll.prototype = {
            init: function(){
                $(window).unbind('scroll');
                $(window).bind('scroll');
                 this.parentHeight = this.fixedParent.height();// height of container
                 this.fixedParentBottom = this.fixedParent.offset().top+this.fixedParent.height()+50;
                 this.fixedDiv.width(this.fixedParent.width()); //sets width of fixed item. Need this for percentage widths
                 this.fixedDivHeight = this.fixedDiv.height();
                 this.fixedParent.height(this.fixedDivHeight);
                 
                 if(this.fixedParent.hasClass('hug_footer')){
                    this.hugged=true;
                    console.log('fixed');
                 }
                 if(this.footer.offset().top > this.fixedParentBottom){
                     this.bindScroll();
                 }else if (this.hugged){
                    this.fixedDiv.addClass('iframe_stick');
                    this.fixedParent.removeClass('hug_footer'); 
                    this.hugged = false; 
                    this.bindScroll();
                 }else{
                     this.fixedDiv.removeClass('iframe_stick');
                 }
                
            },
            
            bindScroll: function(){
                var that = this;
                that.containerStart = that.fixedParent.offset().top-that.containerOffset;
                that.footerStart = (that.footer.offset().top -that.parentHeight-that.containerOffset); 
                
                $(window).scroll(function() { 
                    that.scrollTop = $(window).scrollTop();
                    //checks if container left viewport
                    
                    if (that.scrollTop > that.containerStart) {
                        if (!that.fixed){
                            that.fixedDiv.addClass('iframe_stick');
                            that.fixedParent.removeClass('hug_footer');
                            that.fixed = true;
                            //console.log('2');                   
                        }
                        //console.log('1');
                    }
                    //removes fixed when it comes back into the viewport
                    else if (that.fixed){
                        //fixedDiv.removeClass('iframe_stick');
                        that.fixedParent.removeClass('hug_footer');
                        that.fixedParent.height(that.fixedDiv.height());
                        that.fixed = false;
                        that.hugged=false;
                        //console.log('3');                     
                    }
                    //checks footer position and changes fixed to hugged
                    if ( (that.scrollTop>(that.footerStart)) && !that.hugged){
                        that.fixedDiv.removeClass('iframe_stick');
                        that.fixedParent.addClass('hug_footer');
                        that.fixed = true;
                        that.hugged=true;
                        //console.log('4');
                    }else if(that.hugged && (that.scrollTop<that.footerStart)){ //removes hugged
                        that.fixed = false;
                        that.hugged = false;
                        //console.log('5');
                    }
                });//end windowscroll
        
            }//end bindScroll
        };//end FixedScroll.prototype
        //initiates scroll watcher
        var fixed = FixedScroll();