traverse function in javascript object

traverseFunction.js

function traverse(obj) {
    if (obj instanceof Array) {
        for (var i=0; i<obj.length; i++) {
            if (typeof obj[i] == "object" && obj[i]) {
              callback(i);
              traverse(obj[i]);
            } else {
              callback(i, obj[i])
            }
        }
    } else {
        for (var prop in obj) {
            if (typeof obj[prop] == "object" && obj[prop]) {
              //callback(prop);
              traverse(obj[prop]);
            } else {
                if(re.test(obj[prop])== true){
                  console.log(obj[prop]); 
                }
            }                                     
        }
    }
}