Uncaught DOMException: Failed to execute 'send' on 'XMLHttpRequest': The object's state must be OPENED

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Uncaught DOMException: Failed to execute 'send' on 'XMLHttpRequest': The object's state must be OPENED

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#1 by (4 votes)

1

I need to make a synchronous request and the result has given me this error.

Uncaught DOMException: Failed to execute 'send' on 'XMLHttpRequest': The object's state must be OPENED.

The idea behind this code is to make it run one call after another

function requisicaoSincrona(categoria, callback){
     xmlhttp = null;
    if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp = new XMLHttpRequest();
    }
    else {// code for IE6, IE5
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    values = {"modulo":modulo,"categoria":categoria};
    myJsonString = JSON.stringify(values);
    xmlhttp.onreadystatechange = respond;

    xmlhttp.open("POST", "classes/getData.php", true);
    xmlhttp.send(myJsonString);
    //xmlhttp.abort();
    //como o código executado na volta da requisição é a função respond, chamamos o callback aqui
    function respond() {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
            x = document.getElementsByClassName('terceiraEtapa');
            x[0].innerHTML += xmlhttp.responseText;
        }
        //verifica se uma função foi de fato passada, para então chama-la
        if(callback){
            callback.call();
        }
    }
}
function pegaSuporte(){
    requisicaoSincrona(9);

}
  requisicaoSincrona(6,pegaSuporte)

javascript ajax

asked by anonymous 27.09.2017 / 14:42

1 answer

What is protocol-oriented programming? What is the logic to calculate the percentage of victory, draw and defeat?

score 4 · Accepted Answer

When you do not initialize a variable it stays in global scope and can be code-modified at different places without a trace. This creates errors that are very difficult to detect and is "banned" according to best practice rules.

Initialize the variable with const or var if you need to support legacy browsers.

My suggestion is:

function requisicaoSincrona(categoria, modulo, destino, callback) {
  var xmlhttp = null;
  if (window.XMLHttpRequest) {
    // code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp = new XMLHttpRequest();
  } else {
    // code for IE6, IE5
    xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');
  }
  var values = {
    modulo: modulo,
    categoria: categoria
  };
  var myJsonString = JSON.stringify(values);
  xmlhttp.onreadystatechange = respond;

  xmlhttp.open('POST', 'classes/getData.php', true);
  xmlhttp.send(myJsonString);
  //xmlhttp.abort();
  //como o código executado na volta da requisição é a função respond, chamamos o callback aqui
  function respond() {
    if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
      destino.innerHTML += xmlhttp.responseText;
    }
    //verifica se uma função foi de fato passada, para então chama-la
    if (callback) callback.call();
  }
}
var x = document.getElementsByClassName('terceiraEtapa')[0];
requisicaoSincrona(6, modulo, x, function() {
  requisicaoSincrona(9, modulo, x);
});