通过ajax获取返回值 [英] Getting a return value via ajax
问题描述
我有一个python脚本，我正在使用按钮和带有ajax的javascript从表单中调用该脚本.我真的很难到达python脚本返回的返回变量.
I have a python script which I'm calling from within a form using a button and some javascript with ajax. I'm really struggling to get to the returned variable which the python script returns.
所有返回的信息似乎是按错误的顺序发生的，可能不是这种情况，而是它对我的外观.我想要的只是能够获取python脚本返回的数据.如此简单的事情怎么会如此困难！
The information which is getting returned all seems to be happening in the wrong order, which is probably not the case but its how it looks to me. All I want is to be able to get the data which my python script returns. How can something so simple be so hard!!
任何帮助将不胜感激.谢谢
Any help will be appreciated. Thanks
这是我的代码:
<script>
function drawgraph() {
var x = draw()
alert(x)
};
</script>
<script>
function draw() {
alert("Hello");
$.ajax({
url: "/currentcost.py",
success: function(response){
alert("Success");
return response;
//here you do whatever you want with the response variable
}
});
alert("World");
}
</script>
我得到的答复是你好"，世界"，未定义"和成功"
The responses I get are "Hello", "World", "Undefined" and "Success"
这对我说ajax函数实际上直到我的javascript函数完成后才真正完成，这实际上并不能帮助我真正掌握返回的变量，因此以后可以在javascript中使用它
This says to me the ajax function isn't actually completing until AFTER my javascript function has finished which doesn't help me actually get hold of the returned variable so I can use it in the javascript later on
克里斯
编辑.
<head>
<title>Line Chart</title>
<script>
var ajaxResponse = ""
</script>
<script src="Chart.js"></script>
<script src="jquery.js"></script>
<script>
function drawgraph() {
function handleResponse(response) {
ajaxResponse = response;
}
draw(handleResponse);
};
function draw(handleResponse) {
$.ajax({
url: "/currentcost.py",
success: function(response){
handleResponse(response);
}
});
}
</script>
<script>
function alertbox() {
alert(ajaxResponse);
}
</script>
Currentcost.py:
Currentcost.py:
导入MySQLdb
def index(req):dtbox = req.form.getfirst('dt'，'')tmbox = req.form.getfirst('tm'，'')
def index(req): dtbox = req.form.getfirst('dt', '') tmbox = req.form.getfirst('tm', '')
con = MySQLdb.connect('localhost', 'root', '', 'mydb')
with con:
cur = con.cursor(MySQLdb.cursors.DictCursor)
s = "SELECT tmp, watts FROM currentcost WHERE dt ='" + dtbox + "' and tm like '" + tmbox + "%'"
cur.execute (s)
rows = cur.fetchall()
x=""
y=""
for row in rows:
x=x+row["watts"]+","
y=y+row["tmp"]+","
x="data:["+x+"]"
y="data:["+y+"]"
con.close()
req.write(x)
推荐答案
JavaScript是异步的.当您警告 x 时，很可能是 undefined ，因为尚未收到ajax响应，或者甚至没有启动ajax.传递一个可以处理响应的回调函数，而不是返回它:
Javascript is asynchronous. When you alert x it will most likely be undefined because the ajax response is not received yet, or ajax is not even started. Pass a callback function that can handle the response, instead of returning it :
//global variable holding the response
//substitutes your x
var ajaxResponse;
function drawgraph() {
function handleResponse(response) {
ajaxResponse = response;
//here you may want to do something with the response
//like calling a function that uses the global variable ajaxResponse
//alert(response);
}
draw(handleResponse);
};
function draw(handleReponse) {
$.ajax({
url: "/currentcost.py",
success: function(response){
handleResponse(response);
}
});
}
编辑
在我的小测试中，我只是在
Edit
In my little test I just called drawgraph in a
$(document).ready(function() {
drawgraph();
}
例如，页面加载时.一次.您不清楚如何触发它.如果单击按钮，并且按钮 id 是"button"，则< button id ="button"> click</button>
Eg, on page load. Once. It was onclear how you wanted to trigger it. If click on a button, and the button id is "button", <button id="button">click</button>
$('#button').click(function() {
drawgraph();
}
执行链:
- 某事叫drawgraph
- drawgraph调用draw并传递一个回调函数
- 成功执行ajax时，将在响应中调用回调函数
由于javascript是异步的，因此必须等待"，然后才能继续进行其余的代码"，并且最好的方法是从$ .ajax成功内部继续执行.
Because javascript is asynchronous, you have to "wait" before you can "carry on with the rest of the code", and the best way is to continue execution from inside $.ajax success.
这篇关于通过ajax获取返回值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
