检查Cookie是否存在？

Question

I am trying to find out if a cookie exists or not, if it doesn't I want to create it. I am doing this in Internet Explorer and its stopping at if(readCookie(count) == null) of the code below.

if(readCookie("count") == null)
{
    createCookie("count", 0, 10);
}


function readCookie(name) 
{
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for(var i=0;i < ca.length;i++) 
    {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    }
    return null;
}

What am I doing wrong here?

Answer 1

if( $.cookie('query') == null ) { 
    createCookie("count", 0, 10);
}

Answer 2

Try using undefined instead of null

See the following link:

http://jsfiddle.net/sssonline2/D38WM/1/

Tested on both IE and FireFox

Here's a Stack Overflow link for more info:

typeof !== "undefined" vs. != null