how to read javascript variable from ajax success callback function
Question
I am doing
$.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
<script>var loginStatus = 'false'</script>
if(loginStatus !== 'false') does not work in the success. What am I doing wrong?
The response looks like this
<!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 answers
solution1
3 ACCPTED 2016-05-12 04:00:36
The solution is not pretty. This would be much easier if the response was JSON. Why can't I parse a Ajax html GET response in jQuery? provides hints to a potential solution.
You will have to parse the HTML that gets returned. 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.
UPDATE (DON'T DO THIS):
Again, disclaimer, this is bad practice , but it's possible. The following is just a proof of concept applied to your code. There is also a JSFiddle with the basic idea. 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.
$.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
solution2
1 2016-05-12 03:58:52
I think you can't access a variable inside ajax return because its javascript is not interpreted.
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:
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.
solution3
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
// check the username and password if it matches with the username and password in the database . then echo "YES" otherwise echo "NO"
i explained this login concept using PHP scripting language.
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