javascript - Comparison operators !== against 0 -

i think obvious code does.

why code return whole string if use !== operator? know arrays in javascript start @ index 0, , here i'm entering whole filename argument, indexof(".") greater 0. no, i'm not passing .htaccess file here.

function getfileextension(i) {      // return file extension (with no period) if has one, otherwise false    if(i.indexof(".") !== 0) { //         return i.slice(i.indexof(".") + 1, i.length);    } else {        return false;    } }  // here go! given filename in string (like 'test.jpg'),  getfileextension('pictureofmepdf'); return given string // both operand same type , value 

but if change comparasion

(i.indexof(".") > 0) // logs false  

p.s. case asking, form usvsth3m.

indexof() returns index of substring, can return 0, mean substring appears @ position 0. if substring not found, returns -1 instead, change if statement reflect logic:

if(i.indexof(".") >= 0) 

additionally, should use substring() extract substring string - slice() arrays.

return i.substring(i.indexof(".") + 1, i.length); 

still, think better way split():

var filenamearray = i.split("."); // "foo.txt" --> ["foo" "txt"] if(filenamearray.length >= 2) {     return filenamearray[1]; } else {     return false; //maybe want return "" instead? }