下拉值没有出现在第二个列表中，尝试了一切。当用户选择国家时，状态应该从DB填充到第二个下拉，请帮助。代码：
Javascript部分用于从第1个下拉列表中获取选定值并设置第2个下拉列表
<script type="text/javascript">
function showUser(str)
{
if (str=="")
{
document.getElementById("statename").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("statename").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","getstate.php?q="+str,true);
xmlhttp.send();
}
</script>
Html部分：
<option value="" >Select One</option>
<option value="Afghanistan" >Afghanistan</option>
<option value="Aland Islands" >Aland Islands</option>
<option value="Albania" >Albania</option>
<option value="Algeria" >Algeria</option>
<option value="American Samoa" >American Samoa</option>
<option value="Andorra" >Andorra</option>
<option value="Angola" >Angola</option>
<option value="Anguilla" >Anguilla</option>
<option value="Antarctica" >Antarctica</option>
<option value="Antigua and Barbuda" >Antigua and Barbuda</option>
<option value="Argentina" >Argentina</option>
<option value="Armenia" >Armenia</option>
<option value="Aruba" >Aruba</option>
<option value="Australia" >Australia</option>
<option value="Austria" >Austria</option>
<option value="Azerbaijan" >Azerbaijan</option>
<option value="Bahamas" >Bahamas</option>
<option value="Bahrain" >Bahrain</option>
<option value="Bangladesh" >Bangladesh</option>
<option value="Barbados" >Barbados</option>
<option value="Belarus" >Belarus</option>
<option value="Belgium" >Belgium</option>
<option value="Belize" >Belize</option>
<option value="Benin" >Benin</option>
<option value="Bermuda" >Bermuda</option>
<option value="Bhutan" >Bhutan</option>
<option value="Bolivia" >Bolivia</option>
<option value="Bosnia and Herzegovina" >Bosnia and Herzegovina</option>
<option value="Botswana" >Botswana</option>
<option value="Bouvet Island" >Bouvet Island</option>
<option value="Brazil" >Brazil</option>
<option value="British Indian Ocean Territory" >British Indian Ocean Territory</option>
<option value="British Virgin Islands" >British Virgin Islands</option>
<option value="Brunei" >Brunei</option>
<option value="Bulgaria" >Bulgaria</option>
<option value="Burkina Faso" >Burkina Faso</option>
<option value="Burundi" >Burundi</option>
<option value="Cambodia" >Cambodia</option>
<option value="Cameroon" >Cameroon</option>
<option value="Canada" >Canada</option>
<option value="Cape Verde" >Cape Verde</option>
<option value="Cayman Islands" >Cayman Islands</option>
<option value="Central African Republic" >Central African Republic</option>
<option value="Chad" >Chad</option>
<option value="Chile" >Chile</option>
<option value="China" >China</option>
<option value="Christmas Island" >Christmas Island</option>
<option value="Cocos (Keeling) Islands" >Cocos (Keeling) Islands</option>
<option value="Colombia" >Colombia</option>
<option value="Comoros" >Comoros</option>
<option value="Congo" >Congo</option>
<option value="Cook Islands" >Cook Islands</option>
<option value="Costa Rica" >Costa Rica</option>
<option value="Croatia" >Croatia</option>
<option value="Cuba" >Cuba</option>
<option value="Cyprus" >Cyprus</option>
<option value="Czech Republic" >Czech Republic</option>
<option value="Democratic Republic of Congo" >Democratic Republic of Congo</option>
<option value="Denmark" >Denmark</option>
<option value="Djibouti" >Djibouti</option>
<option value="Dominica" >Dominica</option>
<option value="Dominican Republic" >Dominican Republic</option>
<option value="East Timor" >East Timor</option>
<option value="Ecuador" >Ecuador</option>
<option value="Egypt" >Egypt</option>
<option value="El Salvador" >El Salvador</option>
<option value="Equatorial Guinea" >Equatorial Guinea</option>
<option value="Eritrea" >Eritrea</option>
<option value="Estonia" >Estonia</option>
<option value="Ethiopia" >Ethiopia</option>
<option value="Falkland Islands" >Falkland Islands</option>
<option value="Faroe Islands" >Faroe Islands</option>
<option value="Federated States of Micronesia" >Federated States of Micronesia</option>
<option value="Fiji" >Fiji</option>
<option value="Finland" >Finland</option>
<option value="France" >France</option>
<option value="French Guyana" >French Guyana</option>
<option value="French Polynesia" >French Polynesia</option>
<option value="French Southern Territories" >French Southern Territories</option>
<option value="Gabon" >Gabon</option>
<option value="Gambia" >Gambia</option>
<option value="Georgia" >Georgia</option>
<option value="Germany" >Germany</option>
<option value="Ghana" >Ghana</option>
<option value="Gibraltar" >Gibraltar</option>
<option value="Greece" >Greece</option>
<option value="Greenland" >Greenland</option>
<option value="Grenada" >Grenada</option>
<option value="Guadeloupe" >Guadeloupe</option>
<option value="Guam" >Guam</option>
<option value="Guatemala" >Guatemala</option>
<option value="Guinea" >Guinea</option>
<option value="Guinea-Bissau" >Guinea-Bissau</option>
<option value="Guyana" >Guyana</option>
<option value="Haiti" >Haiti</option>
<option value="Heard Island and Mcdonald Islands" >Heard Island and Mcdonald Islands</option>
<option value="Honduras" >Honduras</option>
<option value="Hong Kong" >Hong Kong</option>
<option value="Hungary" >Hungary</option>
<option value="Iceland" >Iceland</option>
<option value="India" >India</option>
<option value="Indonesia" >Indonesia</option>
<option value="Iran" >Iran</option>
<option value="Iraq" >Iraq</option>
<option value="Iraq-Saudi Arabia Neutral Zone" >Iraq-Saudi Arabia Neutral Zone</option>
<option value="Ireland" >Ireland</option>
<option value="Israel" >Israel</option>
<option value="Italy" >Italy</option>
<option value="Ivory Coast" >Ivory Coast</option>
<option value="Jamaica" >Jamaica</option>
<option value="Japan" >Japan</option>
<option value="Jordan" >Jordan</option>
<option value="Kazakhstan" >Kazakhstan</option>
<option value="Kenya" >Kenya</option>
<option value="Kiribati" >Kiribati</option>
<option value="Kuwait" >Kuwait</option>
<option value="Kyrgyzstan" >Kyrgyzstan</option>
<option value="Laos" >Laos</option>
<option value="Latvia" >Latvia</option>
<option value="Lebanon" >Lebanon</option>
<option value="Lesotho" >Lesotho</option>
<option value="Liberia" >Liberia</option>
<option value="Libya" >Libya</option>
<option value="Liechtenstein" >Liechtenstein</option>
<option value="Lithuania" >Lithuania</option>
<option value="Luxembourg" >Luxembourg</option>
<option value="Macau" >Macau</option>
<option value="Macedonia" >Macedonia</option>
<option value="Madagascar" >Madagascar</option>
<option value="Malawi" >Malawi</option>
<option value="Malaysia" >Malaysia</option>
<option value="Maldives" >Maldives</option>
<option value="Mali" >Mali</option>
<option value="Malta" >Malta</option>
<option value="Marshall Islands" >Marshall Islands</option>
<option value="Martinique" >Martinique</option>
<option value="Mauritania" >Mauritania</option>
<option value="Mauritius" >Mauritius</option>
<option value="Mayotte" >Mayotte</option>
<option value="Mexico" >Mexico</option>
<option value="Moldova" >Moldova</option>
<option value="Monaco" >Monaco</option>
<option value="Mongolia" >Mongolia</option>
<option value="Montserrat" >Montserrat</option>
<option value="Montenegro" >Montenegro</option>
<option value="Morocco" >Morocco</option>
<option value="Mozambique" >Mozambique</option>
<option value="Myanmar" >Myanmar</option>
<option value="Namibia" >Namibia</option>
<option value="Nauru" >Nauru</option>
<option value="Nepal" >Nepal</option>
<option value="Netherlands" >Netherlands</option>
<option value="Netherlands Antilles" >Netherlands Antilles</option>
<option value="New Caledonia" >New Caledonia</option>
<option value="New Zealand" >New Zealand</option>
<option value="Nicaragua" >Nicaragua</option>
<option value="Niger" >Niger</option>
<option value="Nigeria" >Nigeria</option>
<option value="Niue" >Niue</option>
<option value="Norfolk Island" >Norfolk Island</option>
<option value="North Korea" >North Korea</option>
<option value="Northern Mariana Islands" >Northern Mariana Islands</option>
<option value="Norway" >Norway</option>
<option value="Oman" >Oman</option>
<option value="Pakistan" >Pakistan</option>
<option value="Palau" >Palau</option>
<option value="Palestinian Territories" >Palestinian Territories</option>
<option value="Panama" >Panama</option>
<option value="Papua New Guinea" >Papua New Guinea</option>
<option value="Paraguay" >Paraguay</option>
<option value="Peru" >Peru</option>
<option value="Philippines" >Philippines</option>
<option value="Pitcairn Islands" >Pitcairn Islands</option>
<option value="Poland" >Poland</option>
<option value="Portugal" >Portugal</option>
<option value="Puerto Rico" >Puerto Rico</option>
<option value="Qatar" >Qatar</option>
<option value="Reunion" >Reunion</option>
<option value="Romania" >Romania</option>
<option value="Russia" >Russia</option>
<option value="Rwanda" >Rwanda</option>
<option value="Saint Helena and Dependencies" >Saint Helena and Dependencies</option>
<option value="Saint Kitts and Nevis" >Saint Kitts and Nevis</option>
<option value="Saint Lucia" >Saint Lucia</option>
<option value="Saint Pierre and Miquelon" >Saint Pierre and Miquelon</option>
<option value="Saint Vincent and the Grenadines" >Saint Vincent and the Grenadines</option>
<option value="Samoa" >Samoa</option>
<option value="San Marino" >San Marino</option>
<option value="Sao Tome and Principe" >Sao Tome and Principe</option>
<option value="Saudi Arabia" >Saudi Arabia</option>
<option value="Senegal" >Senegal</option>
<option value="Serbia" >Serbia</option>
<option value="Seychelles" >Seychelles</option>
<option value="Sierra Leone" >Sierra Leone</option>
<option value="Singapore" >Singapore</option>
<option value="Slovakia" >Slovakia</option>
<option value="Slovenia" >Slovenia</option>
<option value="Solomon Islands" >Solomon Islands</option>
<option value="Somalia" >Somalia</option>
<option value="South Africa" >South Africa</option>
<option value="South Georgia and South Sandwich Islands" >South Georgia and South Sandwich Islands</option>
<option value="South Korea" >South Korea</option>
<option value="Spain" >Spain</option>
<option value="Spratly Islands" >Spratly Islands</option>
<option value="Sri Lanka" >Sri Lanka</option>
<option value="Sudan" >Sudan</option>
<option value="Suriname" >Suriname</option>
<option value="Svalbard and Jan Mayen" >Svalbard and Jan Mayen</option>
<option value="Swaziland" >Swaziland</option>
<option value="Sweden" >Sweden</option>
<option value="Switzerland" >Switzerland</option>
<option value="Syria" >Syria</option>
<option value="Taiwan" >Taiwan</option>
<option value="Tajikistan" >Tajikistan</option>
<option value="Tanzania" >Tanzania</option>
<option value="Thailand" >Thailand</option>
<option value="Togo" >Togo</option>
<option value="Tokelau" >Tokelau</option>
<option value="Tonga" >Tonga</option>
<option value="Trinidad and Tobago" >Trinidad and Tobago</option>
<option value="Tunisia" >Tunisia</option>
<option value="Turkey" >Turkey</option>
<option value="Turkmenistan" >Turkmenistan</option>
<option value="Turks And Caicos Islands" >Turks And Caicos Islands</option>
<option value="Tuvalu" >Tuvalu</option>
<option value="Uganda" >Uganda</option>
<option value="Ukraine" >Ukraine</option>
<option value="United Arab Emirates" >United Arab Emirates</option>
<option value="United Kingdom" >United Kingdom</option>
<option value="United States" >United States</option>
<option value="United States Minor Outlying Islands" >United States Minor Outlying Islands</option>
<option value="Uruguay" >Uruguay</option>
<option value="US Virgin Islands" >US Virgin Islands</option>
<option value="Uzbekistan" >Uzbekistan</option>
<option value="Vanuatu" >Vanuatu</option>
<option value="vVatican City" >Vatican City</option>
<option value="Venezuela" >Venezuela</option>
<option value="Vietnam" >Vietnam</option>
<option value="Wallis and Futuna" >Wallis and Futuna</option>
<option value="Western Sahara" >Western Sahara</option>
<option value="Yemen" >Yemen</option>
<option value="Zambia" >Zambia</option>
<option value="Zimbabwe" >Zimbabwe</option>
</select>
<h2>State</h2>
<p>
<select name="sub_category" id="statename"></select> </p>
<h2>Select Category </h2>
<input name="" src="http://animalswecare.in/images/search_button.gif" type="image" />
</div>
getstate.php的代码（如果在DB中找到，则用于获取所选国家/地区的状态）
<?php
$q=$_GET["q"];
require_once("../appvars.php");
require_once("../connectuser.php");
$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME) or die("error connecting please refresh or try later");
$query = ("SELECT * FROM ads_DB WHERE country=$q") or die("error querying");
$data=mysqli_query($dbc, $query) or die("error here");
echo "<select name='sub_category'>";
?>
<option value="All" selected>All</option>
<?php
while($row = mysqli_fetch_array($data))
{
?>
<option value="<?php echo $row['state']; ?>" ><?php echo $row['state']; ?></option>
<?php
}
?>
<option value="Other" >Other</option>
<?php
echo "</select>";
mysqli_close($dbc);
?>
</form>
链接是：http://animalswecare.in/ads/adleft.php 我在其他地方使用过类似的代码而且它们正在工作，不知道为什么不在这里工作。
这里为宠物和品种做了同样的事情，它也在起作用：http://animalswecare.in/ads/post-free-pets-animals-ads.php
答案 0 :(得分：1)
尝试这样
SELECT * FROM ads_DB WHERE country='$q'
Bcoz你在where子句中使用字符串值。字符串需要单引号..
希望有所帮助......
答案 1 :(得分：0)
你在打电话给showUser吗？在选择更改？
<select name=blah onchange="showUser()">
答案 2 :(得分：0)
您检查readyState 4 = completed但服务器返回readyState 1 loaded。
答案 3 :(得分：0)
您在提供的链接中收到此错误：
Error: uncaught exception: [Exception... "Not enough arguments [nsIXMLHttpRequest.send]"
nsresult: "0x80570001 (NS_ERROR_XPC_NOT_ENOUGH_ARGS)" location: "JS frame ::
http://animalswecare.in/ads/adleft.php :: showUser :: line 27" data: no]
所以也请尝试
xmlhttp.send(null)
。这可能有所帮助。