无法读取未定义的属性'元素' - 在JS控制台中 [英] Cannot Read Property 'Elements' of Undefined - in JS Console

问题描述

HTML表单（通过PHP输出）

  $ retVal。=< form id ='importSampleDataForm'name =' importSampleDataForm'onsubmit = \return false \> \\\
; 
 
 //编辑表格内容;它包含几十个复选框
 
 $ retVal。= sprintf（< input type ='button'class ='wn_button'onclick ='SaveMotorSkills（）;'value ='导入选定的'> \\ \
）; 
 $ retVal。=< / form> \\\
; 
  

JavaScript / Ajax

 函数SaveMotorSkills（）// {{{
 {
 // {{{Ajax Header 
 var httpRequest = CreateHttpRequest（）; 
 if（！httpRequest）{
 DialogFail（'AJAX initialization error。'，1）; 
返回false; 
} //}}} 
 
 var params ='_SaveMotorSkills = 1'; 
 for（i = 0; i< document.importSampleDataForm.elements.length; i ++）// line with error 
 {
 params + =& + document.importSampleDataForm.elements [i] .name + 
=+ document.importSampleDataForm.elements [i] .value; 
} 
 
 //编辑出AJAX设置
 
 httpRequest.send（params）; 
 DialogSave（Saving ...）; 
} //}}} 
  

请参阅 for 循环。 JS控制台说

Uncaught TypeError：无法读取未定义的属性'元素'

我已经看过这段代码，所以我的眼睛再也看不到它了。有没有其他人看到我不喜欢的东西？我可以添加更多的代码，如果需要的话。

解决方案

尝试

  document.getElementById（'importSampleDataForm'）。elements.length 
  

另外，不允许使用嵌套表单，因此也需要解决。

HTML form (outputed thru PHP)

$retVal .= "<form id= 'importSampleDataForm' name = 'importSampleDataForm' onsubmit = \"return false\" >\n";

    // Form content edited out; it contains several dozen checkboxes

$retVal .= sprintf("<input type='button' class='wn_button' onclick='SaveMotorSkills();' value='Import Selected'>\n");
$retVal .= "</form>\n";

JavaScript / Ajax

function SaveMotorSkills() // {{{
{
    // {{{ Ajax Header
    var httpRequest = CreateHttpRequest();
    if (!httpRequest) { 
        DialogFail('AJAX initialization error. ', 1 );
        return false; 
    } // }}}

    var params = '_SaveMotorSkills=1';
    for(i=0; i<document.importSampleDataForm.elements.length; i++) // line with error
    {
        params += "&" + document.importSampleDataForm.elements[i].name + 
            "=" + document.importSampleDataForm.elements[i].value ;
    }

    // edit out AJAX setup

    httpRequest.send(params);
    DialogSave("Saving...");
} // }}}

See "Line With Error Above" in for loop. JS Console says

Uncaught TypeError: Cannot read property 'elements' of undefined

I have looked at this code so much my eyes can't take it anymore. Does anyone else see anything I don't? I can add more code if needed.

解决方案

Try

document.getElementById('importSampleDataForm').elements.length

Also, nested forms are not allowed, so that also needs to be resolved.

这篇关于无法读取未定义的属性'元素' - 在JS控制台中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！