javascript - JS - Comparing length of words in string, ignoring non-letter chars -

this coderbyte js challenge. goal write function takes in string , returns longest word in string. if 2 words same size first word returned. input never empty. example, input = "fun&!! time" result in: output = "time"

this question has been asked before, although original question involved using variety of string methods , regexp. js (and programming noob) , find approach non-intuitive, , trying assess whether alternate method feasible approach problem:

function longestword(sen) {    var count = '';   var max = 0; //loops thru string & tallies letters in sequences   (i = 0; < sen.length; i++) {        if ((sen.charat(i) >= 'a' && sen.charat(i) <= 'z') ||          (sen.charat(i) >= 'a' && sen.charat(i) <= 'z')) {             count += sen.charat(i); //conditional tracks longest letter string date             if (count.length > max){                 max = count;                              }      } //resets count if encounters non letter value in string     else {         count = '';          }     }   return max;  } 

this seems work in recognizes whether or not first char letter or not , logs var count, not iterating through array i'd expected.

is valid approach? or need learn more string methods , regexp before come this? thanks!

the problem occurs due comparison of integer count.length string max

this can solved initializing max empty string max = '' , compare count.length max.length

here working jsfiddle