Question

我在for循环中有一个变量，即使我已将其设为全局，也无法在外部访问。为什么我无法访问它？变量是＆＃34; finalVar＆＃34;这是代码：

  $(function(){
    var successfullStatements = $("#successfullStatements"),
        errors = $("#errors")

    html5sql.process(
         [{
             sql:"SELECT * FROM StarWarsCharacters WHERE name=?;",
             data:[Jsonvar]
         }],
         function(transaction, results, rowsArray){
             for(var i = 0; i < rowsArray.length; i++){
                //the variable I tried to make global
                 window.finalVar = rowsArray[i].name;

             }

         },
         function(error, statement){

         }
    );
  });
  });

  alert(finalVar); //tried checking to see if variable could be accessed

Answer 1

html5sql.process是一个异步函数。因此，除非执行传递给finalVar的函数，否则不会填充html5sql.process。但是只有在获取results时才会执行。因此，您可能需要将alert移动到result实际填充的位置。

$(function() {
    var successfullStatements = $("#successfullStatements"),
        errors = $("#errors")
        html5sql.process(
            [{
                sql: "SELECT * FROM StarWarsCharacters WHERE name=?;",
                data: [Jsonvar]
            }],
            function(transaction, results, rowsArray) {
                for (var i = 0; i < rowsArray.length; i++) {
                    //the variable I tried to make global
                    alert(rowsArray[i].name);
                }
            },
            function(error, statement) {}
        );
});

Answer 2

   try this:

   html5sql.process(
     [{
         sql:"SELECT * FROM StarWarsCharacters WHERE name=?;",
         data:[Jsonvar],
         async:false
     }],
     function(transaction, results, rowsArray){
         for(var i = 0; i < rowsArray.length; i++){
            //the variable I tried to make global
             window.finalVar = rowsArray[i].name;

         }

     },
     function(error, statement){

     }
);

Please note the function is called asynchronously here.so you have to make the function call synchronous by making "async:false". Then you can get the variable's value outside the for loop.

为什么我无法访问此全局变量？

2 个答案: