How can I stop the output of a loop being printed twice

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I want to make a program that gives a list of the people in space.

This is what i want the output to be like:

name1 name2 name3

but this is the result:

name1 name2 name3 name1 name2 name3

What do i do?
thanks

What I have tried:

HTML

<div id="space_astronauts">
    <span id="child_1"></span>
</div>

JavaScript

var space = new XMLHttpRequest();
space.open("GET", "http://api.open-notify.org/astros.json", "jsonp");
space.send(null);
space.onreadystatechange = function() {
	var res = JSON.parse(space.response);
	
	var totalPeople = res.number;
	for (i = 0; i < totalPeople; i++) {
		var pElement = document.getElementById("space_astronauts");
		var firstChild = pElement.firstChild;
		var astronautsElement = document.createElement("a");
   		var txt = document.createTextNode(res.people[i].name + " ");
   		astronautsElement.appendChild(txt);

   		pElement.insertBefore(astronautsElement, firstChild);
   	}
}

Posted 11-Feb-17 11:13am

Member 12995525

Updated 11-Feb-17 19:36pm

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Comments

Peter Leow 11-Feb-17 22:50pm

show an example of the content of space.response? and what is res.number?

Karthik_Mahalingam 12-Feb-17 1:37am

http://api.open-notify.org/astros.json

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Karthik_Mahalingam · Accepted Answer · 2017-02-11T19:36:00

if (this.readyState == 4 && this.status == 200) {
the above condition is missing in the response, which leads to print the data twice.

var space = new XMLHttpRequest();
       space.open("GET", "http://api.open-notify.org/astros.json", "jsonp");
       space.send(null);
       space.onreadystatechange = function () {
           if (this.readyState == 4 && this.status == 200) {
               var res = JSON.parse(space.response);

               var totalPeople = res.number;
               for (i = 0; i < totalPeople; i++) {
                   var pElement = document.getElementById("space_astronauts");
                   var firstChild = pElement.firstChild;
                   var astronautsElement = document.createElement("a");
                   var txt = document.createTextNode(res.people[i].name + " ");
                   astronautsElement.appendChild(txt);

                   pElement.insertBefore(astronautsElement, firstChild);
               }
           }
       }