如何检查 ajax/php 响应异步？

Question

此代码无效，因为它始终 return 未定义。在我看来，ajax 的“成功”应该 return，如果有结果的话。

如何确保布尔值将被 returned？

<script>
        $('#sbtn').on("click", function(e) {
                e.preventDefault();
                
                // if user exists, set validated to true
                var validated = checkUser('requestedUser');
                
                
                
                // if the user is validated, submit form
                if(validated) {
                    //alert("Thank You");
                    $('#setup').submit();
                }
        }
        
        function checkUser(user) {
                
                data = {
                    lernsax_email: user
                }
                
                $.ajax({
                  type: "POST",
                  url: "checkuser.php",
                  data: data,
                  success: function(msg){
                        if(msg === "passed") {
                            // php returns "passed", if the user can be found
                            console.log(msg);
                            return true;
                            
                        }   else {
                            console.log(msg);
                            return false;
                        }               
                        
                    },
                  
                });
        }
    
    
</script>

Answer 1

你可以使用Promise

<script>
    $('#sbtn').on("click", function(e) {
            e.preventDefault();
            
            // if user exists, set validated to true
            let result = checkUser('requestedUser');
            result.then(validated => {
                if(validated) {
                    //alert("Thank You");
                    $('#setup').submit();
                }
            });
    }
    
    function checkUser(user) {
            data = {
                lernsax_email: user
            }
            return new Promise(resolve => {
                $.ajax({
                  type: "POST",
                  url: "checkuser.php",
                  data: data,
                  success: function(msg){
                        if(msg === "passed") {
                            // php returns "passed", if the user can be found
                            console.log(msg);
                            resolve(true);
                            
                        }   else {
                            console.log(msg);
                            resolve(false);
                        }               
                        
                    },
                  
                });
            });
    }
</script>

或移动

if(validated) {
   //alert("Thank You");
   $('#setup').submit();
}

到 ajax

的成功函数

<script>
    $('#sbtn').on("click", function(e) {
            e.preventDefault();
            
            // if user exists, set validated to true
            checkUser('requestedUser');
    }
    
    function checkUser(user) {
            
            data = {
                lernsax_email: user
            }
            
            $.ajax({
              type: "POST",
              url: "checkuser.php",
              data: data,
              success: function(msg){
                    if(msg === "passed") {
                        // php returns "passed", if the user can be found
                        console.log(msg);
                        $('#setup').submit();
                        return true;
                        
                    }   else {
                        console.log(msg);
                        return false;
                    }               
                    
                },
              
            });
    }
</script>

如何检查 ajax/php 响应异步？

How to check ajax/php response async?

javascript

php

ajax

jquery