基本上我遇到的问题是，当选择框"分级"发生变化时，我有一段脚本被设置为执行。基本上，文档中发生的事情永远不会准备好。当我使用Chrome的控制台打印出学生和梯度值时，它们是空的。我在displayeval.php页面中添加了一个"exit();"函数，结果发现文档永远不会准备好。
我意识到很多代码是混乱的，非常新手，但我像个疯子一样工作，在周末上课之前完成这个项目，我只是想让它工作。
$(document).ready(function () {
$('#graded').change(function () {
var studentid = $('#studentid').val();
var graderid = $(this).val();
$.get("displayeval.php?graderid=" + graderid + "&studentid=" + studentid, function (data) {
$('#behavior-290').val(data.comment);
}, "json");
});
});
instructoreval.php
<?php
include('includes/header.php');
$student_id=$_GET['studentid'];
if($session->userlevel>=8)
//if they are an instructor
{
if(isset($_POST['Submit'])){
$query="SELECT * FROM Behavior b, Groups g WHERE g.GROUP_ID=" . $session->GROUP_ID . " AND b.CONTRACT_ID=g.CONTRACT_ID";
$btwo = mysql_query($query) or die(mysql_error());
$numB = mysql_num_rows($btwo);
$query2="INSERT INTO Eval (STUDENT_ID, Grader_ID, GROUP_ID, Grade) VALUES (" . $_POST[graded] . ", " . $session->STUDENT_ID . ", " . $session->GROUP_ID . ", '10')";
mysql_query($query2) or die(mysql_error());
$evalid = mysql_insert_id();
for($i=0;$i<$numB;$i++){
$r2 = mysql_fetch_array($btwo);
$query3="INSERT INTO EvalComment (CONTRACT_ID, BEHAVIOR_ID, Comment, EVAL_ID) VALUES (" . $r2[CONTRACT_ID] . ", " . $r2[BEHAVIOR_ID] . ", '"" . $_POST[$r2[BEHAVIOR_ID]] . "'", " . $evalid . ")";
mysql_query($query3) or die(mysql_error());
};
$qfour = mysql_query("SELECT * FROM users WHERE GROUP_ID=" . $session->GROUP_ID . " AND STUDENT_ID=" . $_POST[graded]);
$rfour = mysql_fetch_array($qfour);
popup("Your comments for " . $rfour[lname] . ", " . $rfour[fname] . " have been submitted.");
};
$link = mysql_connect("localhost","drallen1","unicode") or die(mysql_error);
mysql_select_db("drallen1");
$qsix = mysql_query("SELECT * FROM users u WHERE u.GROUP_ID=" . $session->GROUP_ID . " AND NOT EXISTS(SELECT * FROM Eval e WHERE u.STUDENT_ID=e.STUDENT_ID) AND u.STUDENT_ID!=" . $session->STUDENT_ID);
$numE = mysql_num_rows($qsix);
/***************************************************
//WHEN numE == 0 GO TO PIE CHART
***************************************************/
//QUERY
$qtwo = mysql_query("SELECT * FROM Behavior b, Groups g WHERE g.GROUP_ID=" . $session->GROUP_ID . " AND b.CONTRACT_ID=g.CONTRACT_ID");
// match eval id
$numB = mysql_num_rows($qtwo);
if($numE>1)
$page="evalform.php";
else
$page="evalprocess.php";
echo "<form action=$page method='"POST'">";?>
<script type="text/javascript">
$(document).ready(function(){
$('#graded').change(
function() {
var studentid = $('#studentid').val();
var graderid = $(this).val();
$.get( "displayeval.php?graderid=" + graderid + "&studentid=" + studentid,
function(data){
$('#behavior-290').val(data.comment);
}, "json");
});
});
</script>
<input type="hidden" name="studentid" id="studentid" value="<?php echo $_GET['studentid'];?>" />
Student: <select name="graded" id="graded">
<option selected="selected">Please Select a Student to Grade</option>
<?php for($i=0;$i<$numE;$i++){
$rsix = mysql_fetch_array($qsix);?>
<option value="<?php echo $rsix[STUDENT_ID]?>"><?php echo $rsix[fname] . " " . $rsix[lname]?></option>
<?php };?>
</select></br></br>
<!--$qthree = mysql_query("SELECT EVAL_ID FROM Eval WHERE GRADER_ID=" . $student_id. " AND STUDENT_ID=" . graded.value ); -->
<?php for($i=0;$i<$numB;$i++){
//result of qtwo
$rtwo = mysql_fetch_array($qtwo);
echo "Behavior: <input name='"BEHAVIOR_ID'" type='"text'" value='"" . $rtwo[BehaviorName] . "'" readonly='"readonly'"/> </br>";
//$queryshit="SELECT Comment FROM EvalComment WHERE EVAL_ID=RESULTFROMQTHREE AND BEHAVIOR_ID=" . $rtwo[BEHAVIOR_ID];
//$comments;
echo "Comments: <textarea name='"" . $rtwo['BEHAVIOR_ID'] . "'" id='"behavior-" . $rtwo['BEHAVIOR_ID'] . "'" rows='"5'" cols='"50'">". $comments . "</textarea> </br>"; ?>
<?php };?>
</br>
<input type="submit" value="Send!" name="Submit"/>
</form>
</body>
</html>
<? include("includes/footer.php");
}else{
echo "You don't have access to this.";
};?>
displayeval.php
<?php
include('include/session.php');
$grader_id=$_GET['graderid'];
$student_id=$_GET['studentid'];
$query="SELECT EVAL_ID FROM Eval WHERE GRADER_ID=". $grader_id . " AND STUDENT_ID=" . $student_id;
$result=mysql_query($query) or die(mysql_error());
$data=mysql_fetch_array($result);
$eval_id=$data['EVAL_ID'];
$query="SELECT BEHAVIOR_ID,Comment comment FROM EvalComment WHERE EVAL_ID=". $eval_id;
$result=mysql_query($query) or die(mysql_error());
$data2=mysql_fetch_assoc($result);
//print_r($data2);
// query database based on GET params
// fetch result
// $mysql_row = mysql_fetch_assoc()
// display in JSON:
echo json_encode( $data2 );
这是displayeval(displayeval.php?graderid=0&studentid=241654664)页面的结果
{"BEHAVIOR_ID":"1","comment":"Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write Write"}
首先，确保$('#graded')元素存在，尝试:
$(document).ready(function() {
alert($('#graded').attr('id')); // should alert 'graded'
});
第二，如果你是动态加载它(在页面呈现之后)，你需要通过$.bind()或$.live()事件声明change()方法。
$('#graded').live('change', function () {
...
});
最后，要小心$.change()。
对于复选框，您可能需要这样做:
$('#graded').change(function(){
if ($(this).is(':checked')) {
// the checkbox is now checked, do something
} else {
// the checkbox is now UN-checked, do something else
}
});
除此之外(KISS原则)，确保jQuery库实际上正在被加载:
if (jQuery) {
alert('jQuery is loaded');
}