Whether the JS query string contains a function of the specified character indexof

Today, using the JS function indexof to see if the string contains the specified character, the first time not to look at, it is used, the results are used to find that the return value of the indexof is the character in the string index, the return value of 0, 1 and so on, if not, will return-1, I see a lot of people on the net Str.indexof (c) >0, this is obviously not right ah, should be str.indexof (c) >-1 Ah, I have been misled, although nothing serious, but this is a warning Ah, code can not be directly copied after the use Ah, Be sure to take a closer look

Whether the JS query string contains a function of the specified character indexof