NSString *headerString = @"<header><meta name='viewport' content='width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no'><style>img{max-width:100%}</style></header>"; [self.webView loadHTMLString:[headerString stringByAppendingString:_model.content] baseURL:nil];
在加载HTML字符串时添加上面的头部限定即可
