javascript - Using XMLHttpRequest in a Google Chrome extension - Stack Overflow

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I started making this simple google chrome extension in javascript. And in the beginning of the code I have the following:

var req = new XMLHttpRequest();

req.open(
    "GET",
    "",
    true);

req.onreadystatechange(alert(req.readyState));

The value req.readyState es to be 1, which means the required page has not been properly fetched. I'm a newbie to Javascript. What's the problem in my code?

I started making this simple google chrome extension in javascript. And in the beginning of the code I have the following:

var req = new XMLHttpRequest();

req.open(
    "GET",
    "http://www.ldoceonline./dictionary/manga",
    true);

req.onreadystatechange(alert(req.readyState));

The value req.readyState es to be 1, which means the required page has not been properly fetched. I'm a newbie to Javascript. What's the problem in my code?

• javascript
• xmlhttprequest

Share Improve this question Follow edited Jul 13, 2010 at 14:13 James 112k3232 gold badges164164 silver badges177177 bronze badges asked Jul 13, 2010 at 14:12 thameerathameera 9,5131010 gold badges3838 silver badges4040 bronze badges

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2 Answers 2

Sorted by: Reset to default 3

how about something like this

var request = new XMLHttpRequest();

if (request == null){
        alert("Unable to create request");
    }else{

        var url = "http://www.ldoceonline./dictionary/manga";

        request.onreadystatechange = function()
            {
            if(request.readyState == 4)
            {
                LDResponse(request.responseText);
            }
        }

        request.open("GET", url, true);
        request.send(null);
    }

function LDResponse(response)
{
// do stuff with the response
}

Of course this is all assuming that they are giving you valid data back ie XML or json

On this line:

req.onreadystatechange(alert(req.readyState));

alert() is being called straight away, which I'm sure isn't your intention. It seems that you want to wait for the onreadystatechange event to fire and then alert the readyState. If that's the case then try this:

req.onreadystatechange = function() {
    alert(req.readyState);
};

And don't forget req.send(null)!

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