INVALID_STATE_ERR: DOM Exception 11

Question

I\'m developing a simple auxiliary class to send requests using XmlHttpRequest (code below). But I cant make it work. At google chrome, for example, I get the error INVALI

Answer 1

Regardless, you can simplify your SendRequest method by creating a mixin instead of using a giant switch.

XRequest.prototype.SendRequest = function(params) {
    var defaultParams = {
        async:    true,
        type:     "",
        url:      "",
        username: "",
        password: "",
        body:     null,
        success:  null,
        failure:  null
    };

    for ( var i in defaultParams ) {
        if ( defaultParams.hasOwnProperty(i) && typeof params[i] == "undefined" ) {
            params[i] = defaultParams[i];
        }
    }

    var that = this;
    this.XHR.onreadystatechange = function() {
        if ( that.XHR.readyState == 4 ) {
            if ( that.XHR.status == 200 || that.XHR.status == 0 ) {
                if ( params.success ) {
                    params.success(that.XHR);
                }
            } else {
                if ( params.failure ) {
                    params.failure();
                }
            }
        }
    };

    this.XHR.open(
        params.type, parms.url, params.async, params.username, params.password
    );

    // It doesn't make sense to have a for/switch here when you're only handling
    // one case
    if ( params.setHeader ) {
        var h = params.setHeader.split(":");
        if ( h.length == 2) {
            this.SetRequestHeader(h[0], h[1]);
        }
    }

    this.XHR.send(params.body);
};

Also be careful: your existing for..in loops have two distinct problems:

1. You're not using var and causing a global to be created: for (e in args) should be for (var e in args)
2. Whenever you use for..in, you should always check to make sure that each key is a direct member of the object, and not something inherited inadvertently through prototype

.

for ( var i in obj ) {
    if ( obj.hasOwnProperty(i) ) {
        // do stuff here
    }
}