<script>
var str = 'qqssddqeqwreqyeiwfhhkasdbcmzxnvakjhdgfiweuryowheflkljsbbdmnbvkajsjehriiuwue';
quChon(str)
function quChon(str) {
var newStr = '';
for (var i = 0; i < str.length; i++) {
if (newStr.indexOf(str.charAt(i)) == -1) {
newStr += str.charAt(i)
}
}
for (var j = 0; j < newStr.length; j++) {
var count = 0;
for (var k = 0; k < str.length; k++) {
if (newStr[j] == str[k]) {
count++;
}
}
document.write(newStr[j] + '出现了' + count + '次' + '<br>')
}
}
</script>
第二种方法
<script>
var str = 'qqssddqeqwreqyeiwfhhkasdbcmzxnvakjhdgfiweuryowheflkljsbbdmnbvkajsjehriiuwue';
var str2 = '';
for (var c of str) {
if (str2.indexOf(c) === -1) {
str2 += c;
}
}
for (var c of str2) {
count = 0;
for (var d of str) {
if (c == d) {
count++;
str = str.replace(d, '')
}
}
document.write(c + '出现了' + count + '次' + '<br>')
}
</script>