<span id="status">qdqwdLED STATUS: OFF</span>
<button id="btn">ON</button>
<script>
var btn = document.getElementById('btn'); var opend = false;
var status = document.getElementById('status'); console.log(status);
console.log(status.innerHTML);
btn.onclick = function() { // var status = document.getElementById('status');
// console.log(status);
// console.log(status.innerHTML);
if (opend) { this.innerText = 'OFF';
status.innerHTML = 'LED STATUS: ON';
} else { this.innerText = 'ON';
status.innerHTML = 'LED STATUS: OFF';
}
opend = !opend;
} </script>為什么必須把獲取status放到點(diǎn)擊函數(shù)里面才能獲取到這個(gè)元素，不然status.innerHTML是undefined,這點(diǎn)擊事件函數(shù)里面也可以使用外部的變量不是嗎
js的作用域小問題...
蝴蝶刀刀
2018-09-10 13:38:12
