I have two dropdown lists and I want for example, if value=fetch selected then show second dropdown but it doesn't work.
I have tried with call external PHP file but I was stuck again. I think that the problem is when I call the on change method but I don't know what to type.
function action(dropdown) {
var value = dropdown.options[dropdown.selectedIndex].value;
if (value == 'Fetch'){
document.getElementById("student_list").style.display = "block";
document.getElementById("subject_list").style.display = "none";
}
if(value == 'Count'){
document.getElementById("student_list").style.display = "block";
}
if(value == 'Percentage'){
document.getElementById("subject_list").style.display = "block";
}
}
<body>
<div class="main_container">
<form method="post">
<select name="action" id ="fetch" onchange="action(this.value);">
<option value="" id="action">--Select Action--</option>
<option value="Fetch">Fetch</option>
<option value="Count">Count</option>
<option value="Percentage">Percentage</option>
</select>
<select name="student_name" id ="student_list" onChange="" style="display:none;"> <!--onchange="getNext(this.value);" -->
<option value="">--Select Action --</option>
<option value="All">All Students</option>
<option value="NameS">Student Name</option>
</select>
</form>
</div>
You cannot use a function named "action" please see https://stackoverflow.com/a/37590405/5391965
You should retrieve your values within the function instead of passing it in parameters like so :
function displayStudentList(dropdown) {
let subject = document.getElementById("subject_list").value;
if (subject === 'Fetch') {
document.getElementById("student_list").style.display = "block";
document.getElementById("subject_list").style.display = "none";
}
if (subject === 'Count') {
document.getElementById("student_list").style.display = "block";
}
if (subject === 'Percentage') {
document.getElementById("subject_list").style.display = "block";
}
}<div class="main_container">
<form method="post">
<select name="action" id="subject_list" onchange="displayStudentList()">
<option value="" id="action">--Select Action--</option>
<option value="Fetch">Fetch</option>
<option value="Count">Count</option>
<option value="Percentage">Percentage</option>
</select>
<select name="student_name" id ="student_list" onChange="" style="display:none;">
<!--onchange="getNext(this.value);" -->
<option value="">--Select Action --</option>
<option value="All">All Students</option>
<option value="NameS">Student Name</option>
</select>
</form>
</div>