function foo(chars) {var count = 0;if (!chars.length) return;var _foo = function(chars, tmp) {for (i in chars) {var ch = chars;var t = tmp   ch[i];var ch = delCharAt(chars, i);if (ch.length < 1) {count    ;
//                只打印渐升数的第100位if(count == 100){console.log(count  ':'   t)}} else {_foo(ch, t);}}};_foo(chars, '');
}function delCharAt(s, i) {ss = '';for (j in s) {if (i != j) {ss  = s[j];}}return ss;
}foo('12345');