- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    [MBProgressHUD dismiss];

    // 修改字型顏色
    [webView stringByEvaluatingJavaScriptFromString:@"document.getElementsByTagName('body')[0].style.webkitTextFillColor= 'white'"];

    // 修改所有元素的背景顏色: 用"*"代表所有元素
    NSString *allElementsStr = @"var objs = document.getElementsByTagName('*'
 
);\n"
    "for(var i=0; i<objs.length; i++) {\n"
    "objs[i].style.backgroundColor='#18171A';} \n";
    [webView stringByEvaluatingJavaScriptFromString:allElementsStr];

    // 修改段落背景顏色
    NSString *pStr = @"var objs = document.getElementsByTagName('p');\n"
    "for(var i=0; i<objs.length; i++) {\n"
 

    "objs[i].style.backgroundColor='#0B1F4F';} \n";
    [webView stringByEvaluatingJavaScriptFromString:pStr];

    // 修改div背景顏色
    NSString *divStr = @"var objs = document.getElementsByTagName('div');\n"
    "for(var i=0; i<objs.length; i++) {\n"
    "objs[i].style.backgroundColor='#0B1F4F';} \n";
    [webView stringByEvaluatingJavaScriptFromString:divStr];

    // 修改span背景顏色
    NSString *spanStr
 
 = @"var objs = document.getElementsByTagName('span');\n"
    "for(var i=0; i<objs.length; i++) {\n"
    "objs[i].style.backgroundColor='#0B1F4F';} \n";
    [webView stringByEvaluatingJavaScriptFromString:spanStr];
}