Ajax jquery 异步返回值
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Ajax jquery async return value
提问by Ghandhikus
how can i make this code to return the value without freezing the browser.
You can rewrite this with new method of course.
我怎样才能让这段代码在不冻结浏览器的情况下返回值。
你当然可以用新方法重写它。
function get_char_val(merk)
{
var returnValue = null;
$.ajax({
type: "POST",
async: false,
url: "char_info2.php",
data: { name: merk },
dataType: "html",
success: function(data)
{
returnValue = data;
}
});
return returnValue;
}
var px= get_char_val('x');
var py= get_char_val('y');
EDIT:i need to have at least 20 variables get from php file at other times.
编辑：我需要在其他时间从 php 文件中获取至少 20 个变量。
回答by SLaks
This is not possible.
Javascript runs on the UI thread; if your code waits for the server to reply, the browser must remain frozen.
这不可能。
Javascript 在 UI 线程上运行；如果您的代码等待服务器回复，则浏览器必须保持冻结状态。
Instead, you need to return the value using a callback:
相反，您需要使用回调返回值：
function get_char_val(merk, callback)
{
var returnValue = null;
$.ajax({
type: "POST",
url: "char_info2.php",
data: { name: merk },
dataType: "html",
success: function(data) {
callback(data);
}
});
}
get_char_val('x', function(px) { ... });
get_char_val('y', function(py) { ... });
Note that the two callbacks will run in an unpredictable order.
请注意，这两个回调将以不可预测的顺序运行。
You should modify your design so that you can get all twenty values in a single AJAX request.
For example, you can take a comma-separated list of values, and return a JSON object like { x: "...", y: "..." }.
您应该修改您的设计，以便您可以在单个 AJAX 请求中获得所有二十个值。
例如，您可以采用逗号分隔的值列表，并返回一个 JSON 对象，如{ x: "...", y: "..." }.
回答by Dutchie432
You can not make variable assignments this way (async). you must set the variables in the successhandler.
您不能以这种方式（异步）进行变量分配。您必须在success处理程序中设置变量。
variableArray = new Array();
get_char_val('x');
get_char_val('y');
function get_char_val(merk)
{
var returnValue = null;
$.ajax({
type: "POST",
url: "char_info2.php",
data: { name: merk },
dataType: "html",
success: function(data)
{
variableArray[merk] = data;
}
});
}
Once all of the retrievals are finished you can access the x and y variables by using variableArray[x]and variableArray[y]
完成所有检索后，您可以使用variableArray[x]和访问 x 和 y 变量variableArray[y]
回答by Suhumar
This may not be what you are expecting but you can set async: true if you dont want pause in the browser and so what you want to do with px on success
这可能不是你所期望的，但你可以设置 async: true 如果你不想在浏览器中暂停，那么你想在成功时用 px 做什么
