<p id="demo1">safdafdas</p>
<button id="demo2">计数</button>
var i = 0;
document.getElementById("demo2").onclick = function(){
//i = i - 1;
if (i = 0) {
i = 3
} else {
i = i - 1
};
document.getElementById("demo1").innerHTML = i;
}
纯js写的,点第一次按钮输出-1,然后就不动了,是哪里出了问题