var logo="MARlogoS.jpg";
var rn = Math.random();    //0-1  reassign new value to rn for backsound
rn = (rn*1500);                     //0 to 1500
rn = Math.round(rn);          // make it an integer 0-1500
if (rn<=100) {logo = "MARlogoS.jpg"}                            //   0-100
if (rn>=101 && rn <=200) {logo = "MARlogoS1.jpg"}   // 101 - 200
if (rn>=201 && rn <=300) {logo = "MARlogoS2.jpg"}   // 201 - 300
if (rn>=301 && rn <=400) {logo = "MARlogoS3.jpg"}   // 301 - 400
if (rn>=401 && rn <=500) {logo = "MARlogoS4.jpg"}   // 401 - 500
if (rn>=501 && rn <=600) {logo = "MARlogoS5.jpg"}   // 501 - 600
if (rn>=601 && rn <=700) {logo = "MARlogoS6.jpg"}   // 601 - 700
if (rn>=701 && rn <=800) {logo = "MARlogoS1.jpg"}   // 701 - 800
if (rn>=801 && rn <=900) {logo = "MARlogoS2.jpg"}   // 801 - 900
if (rn>=901 && rn <=1000) {logo = "MARlogoS3.jpg"}   // 901 - 1000
if (rn>=1001 && rn <=1100) {logo = "MARlogoS4.jpg"}   // 1001 - 1100
if (rn>=1101 && rn <=1200) {logo = "MARlogoS5.jpg"}   // 1101 - 1200
if (rn>=1201 && rn <=1300) {logo = "MARlogoS6.jpg"}   // 1201 - 1300
if (rn>=1301 && rn <=1400) {logo = "MARlogoS7.jpg"}   // 1301 - 1400
if (rn>=1401 && rn <=1500) {logo = "MARlogoS7.jpg"}   // 1401 - 1500


// rn = rn.toString();