未捕获的TypeError:无法读取未定义的属性“值” [英] Uncaught TypeError: Cannot read property 'value' of undefined
本文介绍了未捕获的TypeError:无法读取未定义的属性“值”的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一些javascript代码会出现此错误
I have some javascript code that gives this error
Uncaught TypeError: Cannot read property 'value' of undefined
代码:
var i1 = document.getElementById('i1');
var i2 = document.getElementById('i2');
var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] };
if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; }
if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; }
这个错误是什么意思?
推荐答案
看起来像你的一个值,属性键'value'是未定义的。测试 i1
, i2
和 __ i
在执行前定义if语句:
Seems like one of your values, with a property key of 'value' is undefined. Test that i1
, i2
and __i
are defined before executing the if statements:
var i1 = document.getElementById('i1');
var i2 = document.getElementById('i2');
var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] };
if(i1 && i2 && __i.user && __i.pass)
{
if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; }
if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; }
}
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