function getOptionsData()
{
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
{
json_options = JSON.parse(xmlhttp.responseText);
}
}
xmlhttp.open("GET", "getData.php", true);
xmlhttp.send();
}
"json_options"是一个全局变量,应该用XMLHttpRequest的responseText填充,其中包含一个有效的json字符串:
[{"id":"3","model":"NZ/","model1":"","tablenr":"1","tabkey":"SSG/","length":"4","descript":"Schukostecker gerade","matchcode":"","price":"0","pricex":"0","code":"1","textnr":"0","artikelnr":"0","funktion":"Seite 1"},{"id":"4","model":"NZ/","model1":"","tablenr":"1","tabkey":"SWS/","length":"4","descript":"Schuko gewinkelt / angled 90 Grad","matchcode":"","price":"0","pricex":"0","code":"1","textnr":"0","artikelnr":"0","funktion":"Seite 1"}]
此时一切都很好,json_options包含一个有效的 json 对象。
函数"getOptionsData"在函数"createOptionsTable"中调用:
function createOptionsTable()
{
getOptionsData();
var element = null;
for(var i = 0; i < json_options.length; i++)
{
[...]
当我想在这一点上访问"json_options"时,它说它是空的,我不知道为什么。
任何帮助都非常感谢,提前感谢!
在代码中,getOptionsData();
后的代码在调用的成功回调之前执行。 所以你得到json_options
为空
像这样尝试
function getOptionsData(callback)
{
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
{
json_options = JSON.parse(xmlhttp.responseText);
callback();
}
}
xmlhttp.open("GET", "getData.php", true);
xmlhttp.send();
}
function createOptionsTable()
{
var callback = function()
{
var element = null;
for(var i = 0; i < json_options.length; i++)
{
[...]
}
}
getOptionsData(callback);
}
function getOptionsData()
{
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
{
json_options = JSON.parse(xmlhttp.responseText);
for(var i = 0; i < json_options.length; i++)
{
[...]
}
}
}
xmlhttp.open("GET", "getData.php", true);
xmlhttp.send();
}
您的for loop
应该在您实际从 ajax 而不是内部获得响应后执行createOptionsTable()
......