For loop question

[rolwong]

It really drives me crazy. I have the following script:
echo "<SCRIPT LANGUAGE='JavaScript'>\n";
echo "function update_student()\n";
echo "{\n";
echo "var selected_class_no = document.myForm.individual_class_no.value;\n";
for ($i=0;$i<$total_student;$i++) {
$db_class_no = $arr[$i]['class_no'];
echo "if (selected_class_no == '$db_class_no')\n";
echo "{\n";
$db_student_name[] = $arr[$i]['student_name'];
echo "alert ('$i');\n";
echo "}\n";
}
foreach($db_student_name as $tempdata) {
echo "alert ('$tempdata');\n";
}
$student_count = count ($db_student_name);
echo "alert ('$student_count');\n";
echo "}\n";
echo "</SCRIPT>\n\n";

When I echo "alert ('$i')", it only shows me 2 numbers, that means the if-statement only execute twice, but when i echo $student_count, it shows me 6 numbers in the array...>_<

[rolwong]

Let me explain in more details:

Now I have a drop down menu showing the classname. The above php+javascript code mean to create the corresponding student name list of the corresponding selected class.

class no student_name
1 Kelvin
1 Martin
2 Jean
2 Louis
3 Mary
3 Sisi

var selected_class_no is the class no that just selected by the user. Then with this number, I compare it with DB (all data has all been downloaded when the page is loaded).

for ($i=0;$i<$total_student;$i++) {
$db_class_no = $arr[$i]['class_no'];
echo "if (selected_class_no == '$db_class_no')\n";
echo "{\n";
$db_student_name[] = $arr[$i]['student_name'];
echo "alert ('$i');\n";
echo "}\n";
}

This script is to compare the user-selected class_no with DB data, if the user select "1", then Kevlin, Martin would push into a new array and then display. But when i echo $i, it does show if-statment only execute twice, but when i echo count($db_student_name), this array has contained all six student name)

[tomkleijkers]

I don't really understand what you're doing... 😕 😕 😕