CODEWITHSUNDEEP
javascriptmethodsindexof
Wolfpack'08
Wolfpack'08

Reputation: 4128

Why is 'indexOf' not returning anything?

The book I am reading tells me to open up the JavaScript console and try the code "foo: bar".indexOf(":"). I've tried it in many ways. I tried removing quotation marks, putting it inside a show() and alert() function. I just can't seem to tease anything out.

Has something changed in JavaScript? Has the author made a mistake? Am I supposed to get no return? Do I need to append document.write, perhaps? Any help greatly appreciated.

Upvotes: 0

Views: 161

Answers (3)

mplungjan
mplungjan

Reputation: 178413

Yes something changed in Firefox 5+ However the console (ctrl-shift-k) still works

Fx konsole

In the error console (ctrl-shift-J) you will need to wrap it in alert:

enter image description here

Upvotes: 1

Sai Kalyan Kumar Akshinthala
Sai Kalyan Kumar Akshinthala

Reputation: 11844

try like follows, it should work. Generally the indexOf() will return -1 if the value to search for never occurs.

var str="foo:bar";
document.write(str.indexOf(":") + "<br />");

The output should be 3

Upvotes: 1

Frederik.L
Frederik.L

Reputation: 5620

foo:bar is a property definition in json, and indexOf is supposed to deal with a left value (string variable, constant, or at least something that can have characters in it. I don't know why the book you are reading wants you to do this, but it doesn't seem to be correct. The correct way to use indexOf would be :

var myObject = {
   foo:"bar"
}

alert(myObject.foo.indexOf("a"));

Upvotes: 1

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