javascript / json .length为长度3的数组返回1

Question

I have the following javascript:

var emails_array = ["[\"theiremail1\",\"theiremail2\",\"theiremail3\"]"];
var emails_array_length = emails_array.length;
alert("emails array: " + emails_array + "emails array length: " + emails_array_length);

The alert that appears as the result of this code is:

emails array: ["theiremail1","theiremail2","theiremail3"]emails array length: 1

Why isn't it returning 3?

Answer 1

That's an array with only one item:

var emails_array = [
    "[\"theiremail1\",\"theiremail2\",\"theiremail3\"]"
];

What you're likely after:

var emails_array = JSON.parse(["[\"theiremail1\",\"theiremail2\",\"theiremail3\"]"]);

http://jsfiddle.net/wtLo7h7s/

Answer 2

I think because of the escape characters and your initial double quotes "" . I have tested this a couple times and everytime I use your syntax of var emails_array = ["[\\"theiremail1\\",\\"theiremail2\\",\\"theiremail3\\"]"]; the length comes out 1 because of the initial quotes.

Perhaps a simpler string would work?

For certain, var emails_array = ['theiremail1', 'theiremail2', 'theiremail3']; will provide an emails_array.length of 3...

This gives me a .length of 3 in my test environment anyway. If you MUST use your original double bracketing because you actually want a string with brackets in it then the following works for me.

emails_array = ['[theiremail1', 'theiremail2', 'theiremail3]']; which will have a [ in position 0 and ] in position 2 if thats what you want.

The way you currently have your array setup it is actually only 1 length long because your first double quotes "" tell the compiler to see everything as one big string and it cannot see your delimiter , character.