JS-generated GET variables not being read PHP - php

Question

I am using JavaScript to generate a form's action attribute:
$("#select-font").on('change', function(){
var font = $(this).val();
$("#font-family").val(font);
$(this).css({
'font-family': font
});
$("#edit-doc").css({
'font-family': font
});
// BUG IS HERE --->
$('#save')
.attr('src', '/img/icons2/save.png')
.attr('onclick', '$(this).parents("form").submit();');
$('#save')
.parents('form')
.attr('action',
String($('#save')
.parents('form')
.attr('action')) + '&autosave=true');
});
$("#select-font-size")
.on('change', function(){
var size = $(this).val();
$("#edit-doc").css({
'font-size': size
});
$("#font-size").val(size);
// BUG IS HERE --->
$('#save')
.attr('src', '/img/icons2/save.png')
.attr('onclick',
'$(this).parents("form").submit();');
$('#save')
.parents('form')
.attr('action',
String($('#save')
.parents('form')
.attr('action')) + '&autosave=true');
});
The GET variable is passed to the next page; in the URL bar the location shows up as http://localhost/foo/?var1=a&var2=b&autosave=true. However, when I test the GET variable:
if($_GET["autosave"]){
// some code...
}
The condition is not run. Why can't the PHP see the variable?

Answer 1

Rather than using
if($_GET["autosave"]){
// some code...
}
try:
if (isset($_GET["autosave"])) {
// your code...
}
Also when adding handlers try this, rather than using the inline click handler, use jQuery.on()
$('#save')
.attr('src', '/img/icons2/save.png')
.on('click', function(){
$(this).parents("form").submit();
});