动态插入标签

addScript(){

let scriptArr = document.body.getElementsByTagName("script")

let runIn = true

for(var i in scriptArr ){

if(scriptArr[i].src == previewApi){

runIn = false

break;

}

}

if(runIn){

const s = document.createElement('script');

s.type = 'text/javascript';

s.src = previewApi;

document.body.appendChild(s);

}

}