[gabsillis]

var countMult = 1;
var binary = prompt("enter a binary number");
var len = binary.length;
var dec = 0;
var convert = function(){
    for (i=0;i<len;i++){
        if (binary.charAt(len-(i+1)) == 1){
            dec+=countMult;
        }
        countMult = countMult*2;
        console.log(dec);
    }
};
convert();

fixed! it works completely!