如何从ajax成功回调函数读取javascript变量
[英]how to read javascript variable from ajax success callback function
问题描述
I am doing 
我在做
$.ajax({
type: "GET",
url: url, //valid url..The ajax part works fine
dataType: 'html',
success: function(response) {
if (loginStatus !== 'false') {
testFunction(response); //assuming there is a function called testFunction
}
}
});
The response is a mixed content of html and it also contains 响应是html的混合内容，还包含
<script>var loginStatus = 'false'</script>
if(loginStatus !== 'false') does not work in the success. if（loginStatus！=='false'）不能成功运行。 What am I doing wrong? 我究竟做错了什么？
The response looks like this 响应看起来像这样
<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
</head>
<body>
This is a test page
<script>var loginStatus = 'false'</script>
</body>
</html>
3 个解决方案
解决方案1
3 已采纳 2016-05-12 04:00:36
The solution is not pretty. 解决方案不是很好。 This would be much easier if the response was JSON. 如果响应为JSON，则将更加容易。 Why can't I parse a Ajax html GET response in jQuery? 为什么我不能在jQuery中解析Ajax html GET响应？ provides hints to a potential solution. 提供了潜在解决方案的提示。
You will have to parse the HTML that gets returned. 您将必须解析返回的HTML。 The bad part is that the Javascript part will have to be eval d (bad practice!) unless you do some regular expression magic get the value of the variable. 糟糕的是，除非您执行一些正则表达式魔术来获取变量的值，否则Javascript部分必须为eval d（不好的做法！）。
UPDATE (DON'T DO THIS): 更新（不这样做）：
Again, disclaimer, this is bad practice , but it's possible. 同样，免责声明， 这是不好的做法 ，但是有可能。 The following is just a proof of concept applied to your code. 以下仅仅是应用于您的代码的概念证明。 There is also a JSFiddle with the basic idea. 还有一个带有基本思想的JSFiddle 。 Basically, you parse the response with JQuery's .parseHTML method and evaluate the script with .globalEval at which point the variable becomes available to check. 基本上，您使用JQuery的.parseHTML方法解析响应，并使用.globalEval评估脚本，此时可以检查变量。
$.ajax({
type: "GET",
url: url, //valid url..The ajax part works fine
dataType: 'html',
success: function(response) {
var scriptContent = $($.parseHTML(response, document, true)).filter('script').text();
$.globalEval(scriptContent);
// at this point, the variable loginStatus should be defined
if (loginStatus !== 'false') {
testFunction(response); //assuming there is a function called testFunction
}
}
});
Another reference: jQuery - script tags in the HTML are parsed out by jQuery and not executed 另一个参考： jQuery-HTML中的脚本标签由jQuery解析并且不执行
解决方案2
1 2016-05-12 03:58:52
I think you can't access a variable inside ajax return because its javascript is not interpreted. 我认为您无法在ajax返回值内访问变量，因为它的javascript无法解释。
It's not a good idea (and you could have others problems) but you can put the return to some hidden iframe and access the variable inside using something like: 这不是一个好主意（您可能会遇到其他问题），但是可以将返回值放到一些隐藏的iframe中，并使用类似以下内容的方法来访问其中的变量：
document.getElementById("iframeId").contentWindow.loginStatus
If you have control of the page that you are retrieving the ajax result, I recommend you to response only the variable content or a json to manipulate easily in your javascript. 如果您控制要检索ajax结果的页面，建议您仅响应变量内容或json，以便在javascript中轻松进行操作。
解决方案3
0 2016-05-12 03:59:56
$.ajax({
type: "GET",
url: 'loginCheck.php', //valid url..The ajax part works fine
dataType: 'html',
success: function(response) {
if (response == "YES") {
testFunction(response); //assuming there is a function called testFunction
}
}
});
loginCheck.php loginCheck.php
// check the username and password if it matches with the username and password in the database . //检查用户名和密码是否与数据库中的用户名和密码匹配。 then echo "YES" otherwise echo "NO" 然后回显“是”，否则回显“否”
i explained this login concept using PHP scripting language. 我使用PHP脚本语言解释了此登录概念。
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