Question

我无法弄清楚为什么我一直收到此错误：未捕获的TypeError：无法读取null的属性'options' getFSREPlist （匿名函数）

该错误引用了这行代码（21）：

document.getElementById(elementidupdate).options.length=0;

奇怪的是它在我刚刚穿上的这个新谷歌地图api之前工作了。此外，它正在拉国家代码“1”并将其放入下拉列表中，但不是省代码“19”。

这是页面上的脚本：

getFSREPlist('1', 'fsrep-search-province', 'CountryID', '19');getFSREPlist('19', 'fsrep-search-city', 'ProvinceID', '3');           request.send(null);

以下是完整档案：

   function sack(file) {
    this.xmlhttp = null;
    this.resetData = function () {
        this.method = "POST";
        this.queryStringSeparator = "?";
        this.argumentSeparator = "&";
        this.URLString = "";
        this.encodeURIString = true;
        this.execute = false;
        this.element = null;
        this.elementObj = null;
        this.requestFile = file;
        this.vars = new Object();
        this.responseStatus = new Array(2);
    };
    this.resetFunctions = function () {
        this.onLoading = function () {};
        this.onLoaded = function () {};
        this.onInteractive = function () {};
        this.onCompletion = function () {};
        this.onError = function () {};
        this.onFail = function () {};
    };
    this.reset = function () {
        this.resetFunctions();
        this.resetData();
    };
    this.createAJAX = function () {
        try {
            this.xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e1) {
            try {
                this.xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e2) {
                this.xmlhttp = null;
            }
        }
        if (!this.xmlhttp) {
            if (typeof XMLHttpRequest != "undefined") {
                this.xmlhttp = new XMLHttpRequest();
            } else {
                this.failed = true;
            }
        }
    };
    this.setVar = function (name, value) {
        this.vars[name] = Array(value, false);
    };
    this.encVar = function (name, value, returnvars) {
        if (true == returnvars) {
            return Array(encodeURIComponent(name), encodeURIComponent(value));
        } else {
            this.vars[encodeURIComponent(name)] = Array(encodeURIComponent(value), true);
        }
    }
    this.processURLString = function (string, encode) {
        encoded = encodeURIComponent(this.argumentSeparator);
        regexp = new RegExp(this.argumentSeparator + "|" + encoded);
        varArray = string.split(regexp);
        for (i = 0; i < varArray.length; i++) {
            urlVars = varArray[i].split("=");
            if (true == encode) {
                this.encVar(urlVars[0], urlVars[1]);
            } else {
                this.setVar(urlVars[0], urlVars[1]);
            }
        }
    }
    this.createURLString = function (urlstring) {
        if (this.encodeURIString && this.URLString.length) {
            this.processURLString(this.URLString, true);
        }
        if (urlstring) {
            if (this.URLString.length) {
                this.URLString += this.argumentSeparator + urlstring;
            } else {
                this.URLString = urlstring;
            }
        }
        this.setVar("rndval", new Date().getTime());
        urlstringtemp = new Array();
        for (key in this.vars) {
            if (false == this.vars[key][1] && true == this.encodeURIString) {
                encoded = this.encVar(key, this.vars[key][0], true);
                delete this.vars[key];
                this.vars[encoded[0]] = Array(encoded[1], true);
                key = encoded[0];
            }
            urlstringtemp[urlstringtemp.length] = key + "=" + this.vars[key][0];
        }
        if (urlstring) {
            this.URLString += this.argumentSeparator + urlstringtemp.join(this.argumentSeparator);
        } else {
            this.URLString += urlstringtemp.join(this.argumentSeparator);
        }
    }
    this.runResponse = function () {
        eval(this.response);
    }
    this.runAJAX = function (urlstring) {
        if (this.failed) {
            this.onFail();
        } else {
            this.createURLString(urlstring);
            if (this.element) {
                this.elementObj = document.getElementById(this.element);
            }
            if (this.xmlhttp) {
                var self = this;
                if (this.method == "GET") {
                    totalurlstring = this.requestFile + this.queryStringSeparator + this.URLString;
                    this.xmlhttp.open(this.method, totalurlstring, true);
                } else {
                    this.xmlhttp.open(this.method, this.requestFile, true);
                    try {
                        this.xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded")
                    } catch (e) {}
                }
                this.xmlhttp.onreadystatechange = function () {
                    switch (self.xmlhttp.readyState) {
                        case 1:
                            self.onLoading();
                            break;
                        case 2:
                            self.onLoaded();
                            break;
                        case 3:
                            self.onInteractive();
                            break;
                        case 4:
                            self.response = self.xmlhttp.responseText;
                            self.responseXML = self.xmlhttp.responseXML;
                            self.responseStatus[0] = self.xmlhttp.status;
                            self.responseStatus[1] = self.xmlhttp.statusText;
                            if (self.execute) {
                                self.runResponse();
                            }
                            if (self.elementObj) {
                                elemNodeName = self.elementObj.nodeName;
                                elemNodeName.toLowerCase();
                                if (elemNodeName == "input" || elemNodeName == "select" || elemNodeName == "option" || elemNodeName == "textarea") {
                                    self.elementObj.value = self.response;
                                } else {
                                    self.elementObj.innerHTML = self.response;
                                }
                            }
                            if (self.responseStatus[0] == "200") {
                                self.onCompletion();
                            } else {
                                self.onError();
                            }
                            self.URLString = "";
                            break;
                    }
                };
                this.xmlhttp.send(this.URLString);
            }
        }
    };
    this.reset();
    this.createAJAX();
}
var ajax = new Array();

function getFSREPlist(sel, elementidupdate, fsrepvariable, currentvalue) {
    if (sel == '[object]' || sel == '[object HTMLSelectElement]') {
        var FSREPID = sel.options[sel.selectedIndex].value;
    } else {
        var FSREPID = sel;
    }
    document.getElementById(elementidupdate).options.length = 0;
    var index = ajax.length;
    ajax[index] = new sack();
    ajax[index].requestFile = 'http://www.cabcot.com/wp-content/plugins/firestorm-real-estate-plugin/search.php?' + fsrepvariable + '=' + FSREPID + '&cvalue=' + currentvalue;
    ajax[index].onCompletion = function () {
        ElementUpdate(index, elementidupdate)
    };
    ajax[index].runAJAX();
}

function ElementUpdate(index, elementidupdate) {
    var obj = document.getElementById(elementidupdate);
    eval(ajax[index].response);
}

Answer 1

加载DOM时应调用getFSREPlist。我跑了

document.getElementById('fsrep-search-province').options.length=0

来自chrome´s console。页面仍在加载并导致同样的错误。

http://i.imgur.com/GBFizq1.png

未捕获的TypeError：无法读取null的属性'options'

1 个答案: