Jquery checkbox checkbox implements delete before judging

To achieve such a basic requirement, the page has a lot of data, you can delete one or more, delete before the judge is selected at least one, otherwise prompt.

 
function deleteUser() { 
//I wanted to save the contents as STR +="", but I couldn't
//var str; 
var array = new Array(); //The ID used to hold the selected piece of data
var flag; //Determine if one is not selected
$("input[name='selectFlag']:checkbox").each(function() { //Iterate over all checkboxes whose name is selectFlag
if ($(this).attr("checked")) { //Decide whether to select
flag = true; //As long as one is selected and set to true
} 
}) 
if (flag) { 
$("input[name='selectFlag']:checkbox").each(function() { //Iterate over all checkboxes whose name is selectFlag
if ($(this).attr("checked")) { //Decide whether to select
//alert($(this).val()); 
array.push($(this).val()); //Adds the selected value to the array
//str+=$(this).val()+","; 
} 
}) 
//The data to be collectively deleted is passed to the action for processing
window.self.location = "deleteUser?info=" + array; 
} else { 
alert(" Please select at least one user "); 
} 
} 

Background action to receive data for deletion

 
@Override 
public String execute() throws Exception { 
// TODO Auto-generated method stub 
//The foreground is a,b,c format for the transmission of the first decomposed string
String s[] = info.split(","); 
 
if (s.length > 0) { 
for (int i = 0; i < s.length; i++) { 
userDao.deleteUser(s[i]); 
} 
} 
return "success"; 
}