js是如何实现浏览器打印功能的

//js 部分代码var f = document.getElementById(‘printf’);

if (f) {

document.getElementById(“print_content”).removeChild(f);

}

var printhtml = `

${this.ticket.title}

————————————–   

提货点：${this.ticket.pickUpAddress}

商品名称：${this.ticket.commodityName}

下单时间：${this.ticket.paymentTime}   

提货人：${this.ticket.receiver}   

联系电话：${this.ticket.receiverPhone} 

提货码：${this.ticket.pickUpCode}   

提货时间：${this.ticket.submissionTime}

if (!!window.ActiveXObject || “ActiveXObject” in window) { // 针对IE进行适配

var HKEY_Root, HKEY_Path, HKEY_Key;

HKEY_Root = “HKEY_CURRENT_USER”;

HKEY_Path = “\\Software\\Microsoft\\Internet Explorer\\PageSetup\\”;

//设置网页打印的页眉页脚为空

function PageSetup_Null() {

var Wsh = new ActiveXObject(“WScript.Shell”);

HKEY_Key = “header”;

Wsh.RegWrite(HKEY_Root + HKEY_Path + HKEY_Key, “”);

HKEY_Key = “footer”;

Wsh.RegWrite(HKEY_Root + HKEY_Path + HKEY_Key, “”);

HKEY_Key = “margin_left”

Wsh.RegWrite(HKEY_Root + HKEY_Path + HKEY_Key, “0”); //键值设定–左边边界

HKEY_Key = “margin_top”

Wsh.RegWrite(HKEY_Root + HKEY_Path + HKEY_Key, “0”); //键值设定–上边边界

HKEY_Key = “margin_right”

Wsh.RegWrite(HKEY_Root + HKEY_Path + HKEY_Key, “0”); //键值设定–右边边界

HKEY_Key = “margin_bottom”

Wsh.RegWrite(HKEY_Root + HKEY_Path + HKEY_Key, “0”); //键值设定–下边边界

}

printhtml = `

${this.ticket.title}

———————————————— 

提货点：${this.ticket.pickUpAddress}

商品名称：${this.ticket.commodityName}

下单时间：${this.ticket.paymentTime} 

提货人：${this.ticket.receiver}   

联系电话：${this.ticket.receiverPhone} 

提货码：${this.ticket.pickUpCode}   

提货时间：${this.ticket.submissionTime}

}

var iframe = document.createElement(‘iframe’);

iframe.id = ‘printf’;

iframe.style.width = ‘0’;

iframe.style.height = ‘0’;

iframe.style.border = “none”;

document.getElementById(“print_content”).appendChild(iframe);

setTimeout(() => {

iframe.contentDocument.write(printhtml);

iframe.contentDocument.close();

iframe.contentWindow.focus();

iframe.contentWindow.print();

}, 100)