JavaScript未捕获TypeError：无法读取null的属性'firstChild' [英] javascript Uncaught TypeError: Cannot read property 'firstChild' of null

问题描述

我在Google Chrome浏览器中看到以下错误信息， p> Uncaught TypeError：无法读取null的属性'firstChild'

该错误适用于以下js elem.firstChild。 nodeValue = dispmessage; ：

 函数msg（fld，
 msgtype，
 message） {
 if（emptyString.test（message））
 dispmessage = String.fromCharCode（nbsp）; 
 else 
 dispmessage = message; 
 
 var elem = document.getElementById（fld）; 
 elem.firstChild.nodeValue = dispmessage; 
 
 elem.className = msgtype; //设置CSS类来调整消息
}的外观; 
  

想知道有人遇到过类似的问题吗？任何想法如何解决？

干杯

解决方案

错误意味着 elem 对象是 null 。检查传递的fld值，看看具有该id的对象是否实际存在于您的代码中。

I am getting the following error in Google Chrome on a very old Form I inherited (seems to work OK in IE, no errors)

Uncaught TypeError: Cannot read property 'firstChild' of null

The error applies to the following js elem.firstChild.nodeValue = dispmessage;:

function msg(fld,     
         msgtype, 
         message) {
  if (emptyString.test(message))
    dispmessage = String.fromCharCode(nbsp);
  else
    dispmessage = message;

  var elem = document.getElementById(fld);
  elem.firstChild.nodeValue = dispmessage;

  elem.className = msgtype;   // set the CSS class to adjust appearance of message
};

Wondering if someone has come across similar issue before? Any ideas on how I can resolve?

Cheers

解决方案

This error means the elem object is null. Check the fld value passed and see whether an object with that id actually exists in your code or not.

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