Question

I have a drop down which has many options. I want that when I select any
option then it calls a function through JavaScript.

the code which I used is here

<select name="aa" onchange="report(this.value)"> <--- this is function in .js
<option value="daily">daily</option>
<option value="monthly">monthly</option>
</select>

I want when I select daily then function(daily) is invoked
and vice versa.

function report(daily)<-- js function {  
  loadXMLDoc('script/d_report.php','responseTag');
  document.getElementById('responseTag').style.visibility='visible';
  document.getElementById('list_report').style.visibility='hidden';
  document.getElementById('formTag').style.visibility='hidden'; 
} 
function report(monthly) {
  document.getElementById('responseTag').style.visibility='visible';
  loadXMLDoc('script/m_report.php','responseTag');
  document.getElementById('list_report').style.visibility='hidden';
  document.getElementById('formTag').style.visibility='hidden';
}

Answer 1

<select name="aa" onchange="report(this.value)"> 
  <option value="">Please select</option>
  <option value="daily">daily</option>
  <option value="monthly">monthly</option>
</select>

using

function report(period) {
  if (period=="") return; // please select - possibly you want something else here

  const report = "script/"+((period == "daily")?"d":"m")+"_report.php";
  loadXMLDoc(report,'responseTag');
  document.getElementById('responseTag').style.visibility='visible';
  document.getElementById('list_report').style.visibility='hidden';
  document.getElementById('formTag').style.visibility='hidden'; 
} 

---

Unobtrusive version:

<select id="aa" name="aa"> 
  <option value="">Please select</option>
  <option value="daily">daily</option>
  <option value="monthly">monthly</option>
</select>

using

window.addEventListener("load",function() {
  document.getElementById("aa").addEventListener("change",function() {
    const period = this.value;
    if (period=="") return; // please select - possibly you want something else here

    const report = "script/"+((period == "daily")?"d":"m")+"_report.php";
    loadXMLDoc(report,'responseTag');
    document.getElementById('responseTag').style.visibility='visible';
    document.getElementById('list_report').style.visibility='hidden';
    document.getElementById('formTag').style.visibility='hidden'; 
  }); 
});

---

jQuery version – same select with ID

$(function() {
  $("#aa").on("change",function() {
    const period = this.value;
    if (period=="") return; // please select - possibly you want something else here

    var report = "script/"+((period == "daily")?"d":"m")+"_report.php";
    loadXMLDoc(report,'responseTag');
    $('#responseTag').show();
    $('#list_report').hide();
    $('#formTag').hide(); 
  }); 
});