Javascript：如何将值传递给函数参数？

Question

function retrieveHasilRawatJalan()

 function retrieveHasilRawatJalan2(row, kd_klp) { var hasil_rawat_jalan2; var xhttp; if (window.XMLHttpRequest) { xhttp = new XMLHttpRequest(); } else { // code for IE6, IE5 xhttp = new ActiveXObject("Microsoft.XMLHTTP"); } xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function() { if (xhttp.readyState == 4 && xhttp.status == 200) { hasil_rawat_jalan2 = JSON.parse(xhttp.responseText); document.getElementById("type").innerHTML = "type of : " + typeof hasil_rawat_jalan2; document.getElementById("value").innerHTML = "value of {'1' {'klp_id' : [" + hasil_rawat_jalan2[1]['klp_id'] + "]"; document.getElementById("size").innerHTML = "object size :[" + parseInt(Object.size(hasil_rawat_jalan2)) + "]"; document.getElementById("row_start").innerHTML = "start row : " + row; document.getElementById("demo").innerHTML = "content : " + hasil_rawat_jalan2; } } xhttp.open("POST", "../lab/get_row_content_from_lab_code/" + kd_klp + "", true); xhttp.send(); //start from here the code is the same. var number_of_row = parseInt(Object.size(hasil_rawat_jalan2)); addNewRow(number_of_row); } 

variable hasil_rawat_jalan2 contain JSON data and type of this variable is object,

i check type of variable hasil_rawat_jalan2, and call one of the data using this code

document.getElementById("type").innerHTML = "type of : " + typeof hasil_rawat_jalan2;
      document.getElementById("value").innerHTML = "value of {'1' {'klp_id' : [" + hasil_rawat_jalan2[1]['klp_id'] + "]";
      document.getElementById("size").innerHTML = "object size : [" + parseInt(Object.size(hasil_rawat_jalan2)) + "]";
      document.getElementById("row_start").innerHTML = "start row : " + row;
      document.getElementById("demo").innerHTML = "content : " + hasil_rawat_jalan2;

the result is this:

type of : object

value of {'1' {'klp_id' : [HL-004]

object size :[8]

start row : 1

content : [object Object]

the problem is when i put var number_of_row in function addNewRow() it doesnt do anything. but it work if i put number directly like this
addNewRow(8). how to check the error?

Answer 1

The function is asynchronous (XMLHttpRequest is, actually). It means that hasil_rawat_jalan2 is not yet defined when you try to use it, because AJAX request doesn't pause subsequent program execution. You need to move addNewRow into onreadystatechange callback and call it once response has become available:

function retrieveHasilRawatJalan2(row, kd_klp) {

   var hasil_rawat_jalan2;

   var xhttp;
   if (window.XMLHttpRequest) {
     xhttp = new XMLHttpRequest();
   } else {
     // code for IE6, IE5
     xhttp = new ActiveXObject("Microsoft.XMLHTTP");
   }

   xhttp = new XMLHttpRequest();
   xhttp.onreadystatechange = function() {
     if (xhttp.readyState == 4 && xhttp.status == 200) {
       hasil_rawat_jalan2 = JSON.parse(xhttp.responseText);
       document.getElementById("type").innerHTML = "type of : " + typeof hasil_rawat_jalan2;
       document.getElementById("value").innerHTML = "value of {'1' {'klp_id' : [" + hasil_rawat_jalan2[1]['klp_id'] + "]";
       document.getElementById("size").innerHTML = "object size :[" + parseInt(Object.size(hasil_rawat_jalan2)) + "]";
       document.getElementById("row_start").innerHTML = "start row : " + row;
       document.getElementById("demo").innerHTML = "content : " + hasil_rawat_jalan2;

       // Use hasil_rawat_jalan2
       var number_of_row = parseInt(Object.size(hasil_rawat_jalan2));
       addNewRow(number_of_row);
     }
   }
   xhttp.open("POST", "../lab/get_row_content_from_lab_code/" + kd_klp + "", true);
   xhttp.send();
 }