function output(str) {
//删除原有结点
let content = document.querySelector('.content')
let jsBlink = document.querySelector('#jsBlink')
let childs = content.childNodes
while(childs.length > 0){
if(childs[0] == jsBlink){
break;
}
content.removeChild(childs[0]);
}
var i = 0
var fun = setInterval(function(){
if (str.length === i) {
clearInterval(fun)
} else {
var c = str[i]
if (c == '\n') {
var br = document.createElement('br')
content.insertBefore(br,jsBlink)
} else {
var newSpan = document.createElement('span');
newSpan.className = 'word color' + Math.ceil(Math.random()*24)
if(c == '<'){
c = '&lt';
}else if(c == '>'){
c = '&gt';
}else if(c == ' '){
c = '&nbsp';
}
newSpan.innerHTML = c
content.insertBefore(newSpan,jsBlink)
}
i++
}
}, 200)

}