<html> <head> <title>frequency</title> <script> var arr = [1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4]; var a = [], b = [], prev; arr.sort(); for ( var i = 0; i < arr.length; i++ ) { if ( arr[i] !== prev ) { a.push(arr[i]); b.push(1); } else { b[b.length-1]++; } prev = arr[i]; } var result = [a, b]; console.log(result); document.write('[' + result[0] + ']<br>[' + result[1] + ']') </script> </head> <body> </body> </html>