为什么此功能不起作用？

Question

When i click "test" to frame is resized but when i click it again it doesnt resize back to its original size

function dropdownResize(){

var down = 0;

        if(down == 0){
                parent.document.getElementById('frameMain').rows = '84,84,*';
                down = 1;
            }
        else{
                parent.document.getElementById('frameMain').rows = '84,30,*';
                down = 0;
            }


    }

<a onclick="dropdownResize()"> test</a>

Answer 1

It does not work because down is defined within the scope of the function dropdownResize() . When the function is called, down is reset to 0 every time again.

What you should do: (please note that this is a direct answer to your question and you should probably learn more about variable scope in order to prevent global variables as much as possible)

var down = 0;
function dropdownResize(){
        if(down == 0){
                parent.document.getElementById('frameMain').rows = '84,84,*';
                down = 1;
            }
        else{
                parent.document.getElementById('frameMain').rows = '84,30,*';
                down = 0;
            }
    }

Answer 2

try:

var down = 0;

function dropdownResize(){

        if(down == 0){
                parent.document.getElementById('frameMain').rows = '84,84,*';
                down = 1;
            }
        else{
                parent.document.getElementById('frameMain').rows = '84,30,*';
                down = 0;
            }


    }

Answer 3

我认为down是一个局部变量，每次调用该函数时都将其设置为0。