未定义的变量：totalScore。 如何定义此变量，因为它是计算的结果？
问题描述：
Here is the line of code that is in question. I need to define $totalScore but am not sure which method to use, as it is a result variable. I've tried setting it to "0" " " and "null", but those values did not solve the problem. Anyone here know the solution to this so I can display the grade received as an alert?
if ($totalScore >= 900 && $totalScore <= 1000) {alert("Total Points of "+$totalScore+" gives you an A!");}
else if ($totalScore >= 800 && $totalScore <= 899) {alert("Total Points of "+$totalScore+" gives you an B!");}
else if ($totalScore >= 700 && $totalScore <= 799) {alert("Total Points of "+$totalScore+" gives you an C!");}
else if ($totalScore >= 600 && $totalScore <= 699) {alert("Total Points of "+$totalScore+" gives you an D!");}
else if ($totalScore >= 0 && $totalScore <= 599) {alert("Total Points of "+$totalScore+" gives you an F!");} }
Here's the rest of the code for reference!
<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);
?>
<?php
if(isset($_POST['submit'])) {
$name = $_POST['StudentName'];
$quiz = (int)$_POST['QuizScore'];
$assignment = (int)$_POST['AssignmentScore'];
$midterm = (int)$_POST['MidtermScore'];
$final = (int)$_POST['FinalScore'];
$totalScore = NULL ;
$totalScore = $quiz + $assignment + $midterm + $final;
echo "Total Score: " , $totalScore; }
{
if ($totalScore >= 900 && $totalScore <= 1000) {alert("Total Points of "+$totalScore+" gives you an A!");}
else if ($totalScore >= 800 && $totalScore <= 899) {alert("Total Points of "+$totalScore+" gives you an B!");}
else if ($totalScore >= 700 && $totalScore <= 799) {alert("Total Points of "+$totalScore+" gives you an C!");}
else if ($totalScore >= 600 && $totalScore <= 699) {alert("Total Points of "+$totalScore+" gives you an D!");}
else if ($totalScore >= 0 && $totalScore <= 599) {alert("Total Points of "+$totalScore+" gives you an F!");} }
?>
<!DOCTYPE html>
<html>
<head>
<body>
<div align='center'><form name="form1" method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>" >
<input type="text" id="studentName" size="25px" placeholder="Please enter your name" name="StudentName"><br><br>
Total of Quiz Scores (150 possible):<input type="text" id="QuizScore" name="QuizScore" min="1" max="150" size="5"/><br>
Total of Assignment Scores (400 possible):<input type="text" id="AssignmentScore" name="AssignmentScore" min="1" max="400" size="5"><br>
Midterm Score (200 possible):<input type="text" id="MidtermScore" name="MidtermScore" min="1" max="200" size="5"><br>
Final Score (250 possible):<input type="text" id="FinalScore" name="FinalScore" min="1" max="250" size="5"><br>
<input type="submit" value="Calculate your score" name="submit"><br><br>
</form></div>
</body>
</html>
答
See this. improved version of your Code
first thing first you cannot use javascript alert directly inside.
<?php
if(isset($_POST['submit']))
{
$name = $_POST['StudentName'];
$quiz = (int)$_POST['QuizScore'];
$assignment = (int)$_POST['AssignmentScore'];
$midterm = (int)$_POST['MidtermScore'];
$final = (int)$_POST['FinalScore'];
$totalScore = 0;;
$totalScore = $quiz + $assignment + $midterm + $final;
// echo "Total Score: " , $totalScore;
if ($totalScore >= 900 && $totalScore <= 1000) {
$message = "Total Points of ".$totalScore." gives you an A!";
}
else if ($totalScore >= 800 && $totalScore <= 899) {
$message = "Total Points of ".$totalScore." gives you an B!" ;
}
else if ($totalScore >= 700 && $totalScore <= 799) {
$message = "Total Points of ".$totalScore." gives you an C!";
}
else if ($totalScore >= 600 && $totalScore <= 699) {
$message = "Total Points of ".'.$totalScore.'." gives you an D!";
}
else if ($totalScore >= 0 && $totalScore <= 599) {
$message = "Total Points of ".$totalScore." gives you an F!";
}
echo '<script type="text/javascript"> alert("'.$message.'"); </script>';
}
?>
<html>
<head>
<body>
<div align='center'><form name="form1" method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>" >
<input type="text" id="studentName" size="25px" placeholder="Please enter your name" name="StudentName"><br><br>
Total of Quiz Scores (150 possible):<input type="text" id="QuizScore" name="QuizScore" min="1" max="150" size="5"/><br>
Total of Assignment Scores (400 possible):<input type="text" id="AssignmentScore" name="AssignmentScore" min="1" max="400" size="5"><br>
Midterm Score (200 possible):<input type="text" id="MidtermScore" name="MidtermScore" min="1" max="200" size="5"><br>
Final Score (250 possible):<input type="text" id="FinalScore" name="FinalScore" min="1" max="250" size="5"><br>
<input type="submit" value="Calculate your score" name="submit">
<br><br>
</form>
</div>
</body>
</html>
答
I have made some changes please have look on below code, actually you have to declare $totalscore before your post condition and whole code should be in condition.
<?php
$totalScore= 0;
if(isset($_POST['submit'])) {
$name = $_POST['StudentName'];
$quiz = (int)$_POST['QuizScore'];
$assignment = (int)$_POST['AssignmentScore'];
$midterm = (int)$_POST['MidtermScore'];
$final = (int)$_POST['FinalScore'];
global $totalScore;
$totalScore = $quiz + $assignment + $midterm + $final;
echo "Total Score: " , $totalScore;
if ($totalScore >= 900 && $totalScore <= 1000) {alert("Total Points of "+$totalScore+" gives you an A!");}
else if ($totalScore >= 800 && $totalScore <= 899) {alert("Total Points of "+$totalScore+" gives you an B!");}
else if ($totalScore >= 700 && $totalScore <= 799) {alert("Total Points of "+$totalScore+" gives you an C!");}
else if ($totalScore >= 600 && $totalScore <= 699) {alert("Total Points of "+$totalScore+" gives you an D!");}
else if ($totalScore >= 0 && $totalScore <= 599) {alert("Total Points of "+$totalScore+" gives you an F!");} }
?></div>
答
Variable $totalScore will not be initialized, when this condition if(isset($_POST['submit'])) is false, because there are too many { and } in your code. So i would check why the post variable submit is not set, and even more important, initialize the variable in the other case too.
答
You are initializing the $totalScore only if the form was submitted, first you should initialize it with null right from start
<?php
$totalScore = null;
if (isset($_POST['submit']) {
//...
} elseif ($totalScore && (/*your initial conditions*/)) {
//calculate marks
}
If you'd like a more cleaner design i suggest you to use Ajax and in response you will alert the result;