循环问题 [英] problem with loop
问题描述
您好
我有以下功能，在页面加载时调用。
function checkFieldContent（form）{
var field;
for（i = 0; i< form.elements.length; i ++）{
field = form.elements [i];
if（field.type ==''text''）{
alert（field.name）;
// checkSearchInput（field）; < br $>
}
提醒（'''''）;
}
alert（''end''） ;
}
像这样它完美但只要我自己的函数被调用 - >>
checkSearchInput（字段） ）;它只会循环一次，
checkSearchInput调用各种子函数，而且此刻不会返回任何东西。当我需要
在函数调用中返回true或false时，我不是真的很喜欢js并且很困惑。我尝试了返回
值（真或假），但它没有改变任何东西。当然功能
checkSearchInput本身可以正常工作...
非常感谢您的帮助！
sg2923
Hi there
I have following function which is called on load of page.
function checkFieldContent(form) {
var field;
for(i = 0; i < form.elements.length; i++) {
field = form.elements[i];
if (field.type == ''text'') {
alert(field.name);
// checkSearchInput(field);
}
alert(''after'');
}
alert(''end'');
}
Like this it works perfect but as soon as my own function is called ->
checkSearchInput(field); it''s only going one time through the loop,
checkSearchInput calls various subfunctions and at the moment does not
return anything. I''m not really into js and confused about when I need
to return true or false on a functions call. I tried it with a return
value (true or false) but it didn''t change anything. Of course function
checkSearchInput for itself works without errors...
Thanks a lot for your appreciated help!
sg2923
推荐答案
我们*** *@gmx.net 写道：
< snip>
us****@gmx.net wrote:
<snip>
function checkFieldContent（form）{
var field;
for（i = 0; i< form.elements.length; i ++）{
field = form.elements [i];
if（field.type ==''text''）{
alert（field.name）;
// checkSearchInput（field）;
}
alert（''after ''）;
}
提醒（''结束''）;
}
像这样它完美但只要我自己的函数被调用 - >>
checkSearchInput（field）;它只有一次循环，
checkSearchInput调用各种子函数，目前确实没有返回任何东西。
function checkFieldContent(form) {
var field;
for(i = 0; i < form.elements.length; i++) {
field = form.elements[i];
if (field.type == ''text'') {
alert(field.name);
// checkSearchInput(field);
}
alert(''after'');
}
alert(''end'');
}
Like this it works perfect but as soon as my own function is called ->
checkSearchInput(field); it''s only going one time through the loop,
checkSearchInput calls various subfunctions and at the moment does
not return anything.
所以你可以发布一个让每个人都可以使用的代码
猜测实际导致代码的代码是什么问题？
无论如何;你没有声明你的循环计数器 - 我 - 作为一个
函数局部变量（所以它实际上是全局的）。如果在循环中调用的任何
函数使用类似的 - i - 变量，那么
也没有被声明为函数局部变量，并且任何设置它的
超出元素集合长度的值，循环将是
在下一次终止时全局变量 - i - 变量
是检查。
So you though you would post the code that works an leave everyone to
guess as to what is in the code that actually causes the problem?
In any event; you have not declared your loop counter - i - as a
function local variable (so it is effectively global). If any of the
functions called from within the loop use a similar - i - variable that
is also not declared as a function local variable, and any set its
value beyond the length of the elements collection, the loop will be
terminated on the next occasion the value of the global - i - variable
is checked.
我不是真的进入js ...
I''m not really into js ...
< snip>
使用局部变量应该使用的全局变量是一般的编程中的错误
，因此与JS无关。
Richard。
<snip>
Using global variable where local variables should be used is a fault
in programming in general, so not related to JS as such.
Richard.
我们**** @ gmx.net 写道：
us****@gmx.net writes:
我有以下函数在页面加载时调用。
函数checkFieldContent（表单） ）{
var field;
for（i = 0; i< form.elements.length; i ++） {
I have following function which is called on load of page.
function checkFieldContent(form) {
var field;
for(i = 0; i < form.elements.length; i++) {
这里i未声明为局部变量。这意味着
它被创建为全局变量。你应该总是声明
您的变量只有所需的范围，即
将其更改为：
for （var i = 0; i< form.elements.length; i ++）{
Here "i" is not declared to be a local variable. That means that
it is created as a global variable. You should always declare
your variables to have only as much scope as needed, i.e.,
change this to:
for(var i = 0; i < form.elements.length; i++) {
// checkSearchInput（field）;
// checkSearchInput(field);
很可能你在checkSearchInput中有一个类似的循环，
表示全局i的值。通过调用
将变量更改为大于form.elements.length的值。修复那个方法。
（如果调用函数会使你的脚本中断，那么当你提问时包含该函数可能是一个很好的想法求助:)
/ L
-
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML死亡颜色：< URL：http：//www.infimum.dk/HTML/rasterTriangleDOM.html>
''没有判断的信仰只会降低神灵的精神。''
Most likely you have a similar loop in the "checkSearchInput", which
means that the value of the global "i" variable is changed by the call
to something larger than "form.elements.length". Fix that method too.
(If a call to a function makes your script break, it might be a good
idea to include that function when you ask for help :)
/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleDOM.html>
''Faith without judgement merely degrades the spirit divine.''
于2006年8月18日写在comp.lang.javascript ：
wrote on 18 aug 2006 in comp.lang.javascript:
我有以下函数，在页面加载时调用。
函数checkFieldContent（form）{
var field;
for（i = 0; i< form.elements.length; i ++）{
field = form.elements [i];
if（field.type ==''text''）{
alert（field.name）;
// checkSearch输入（字段）;
}
提醒（'''''）;
}
alert（ ''结束''）;
}
像这样它完美但只要我调用自己的函数 - >
checkSearchInput （领域）;它只会循环一次，
checkSearchInput调用各种子函数，而且此刻不会返回任何东西。当我需要
在函数调用中返回true或false时，我不是真的很喜欢js并且很困惑。我尝试了返回
值（真或假），但它没有改变任何东西。当然功能
checkSearchInput本身可以正常工作......
I have following function which is called on load of page.
function checkFieldContent(form) {
var field;
for(i = 0; i < form.elements.length; i++) {
field = form.elements[i];
if (field.type == ''text'') {
alert(field.name);
// checkSearchInput(field);
}
alert(''after'');
}
alert(''end'');
}
Like this it works perfect but as soon as my own function is called ->
checkSearchInput(field); it''s only going one time through the loop,
checkSearchInput calls various subfunctions and at the moment does not
return anything. I''m not really into js and confused about when I need
to return true or false on a functions call. I tried it with a return
value (true or false) but it didn''t change anything. Of course function
checkSearchInput for itself works without errors...
你永远不应该调用变量form。
将表格视为保留字。
在这段代码中你会伤到自己，
，因为你用外部值填充表格
一个名为field
的变量，可能被定义为一个字段
而不是一个表单。
尝试：
==============================
< script type =''text / javascript''>
function checkFieldNames（myForm）{
var myForm = document.getElementById（''thisForm ''）
var myField;
for（var i = 0; i< myForm.elements.length; i ++）{
myField = myForm.elements [i];
if（myField.type ==''text''）
alert（myField.name）;
}
}
< / script>
< body onload =''checkFieldNames（ & thisForm）''>
< form id =''thisForm''>
< input name =''t1' '>
<输入名称=''t2''>
<输入类型=''提交''name ='''跳过''>
<输入名称=''t3''>
< / form>
========= ========================
for（i = 0; ...
应为（var i = 0; ...
但这只会导致问题
如果你有一个全局变量i，
即使这样，上面的函数也不会受到影响。
< input type =''text''中的类型声明是默认的。
-
Evertjan。
荷兰。
（请将x''es更改为我的电子邮件地址中的点数）
You should never call a variable "form".
Treat form as a reserved word.
In this code you hurt yourself,
as you fill the form with a external value
of a variable called field
that probably is defined as a field
and not as a form.
Try:
==============================
<script type=''text/javascript''>
function checkFieldNames(myForm) {
var myForm = document.getElementById(''thisForm'')
var myField;
for(var i = 0; i < myForm.elements.length; i++ ) {
myField = myForm.elements[i];
if (myField.type == ''text'')
alert(myField.name);
}
}
</script>
<body onload=''checkFieldNames("thisForm")''>
<form id=''thisForm''>
<input name=''t1''>
<input name=''t2''>
<input type=''submit'' name=''skipped''>
<input name=''t3''>
</form>
=================================
The for(i = 0;...
should be for(var i = 0;...
but that will only cause problems
if you have a global variable i,
and even then the above function will not be affected.
The type declaration in <input type=''text'' is default.
--
Evertjan.
The Netherlands.
(Please change the x''es to dots in my emailaddress)
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