[英]how to check checkboxes in javascript
我在html中有三个复选框。
在Javascript中,我有可变newspaper = "jang,News,Dawn"
;
现在,我想基于报纸的值检查复选框,如果它仅包含jang,则仅jang复选框应被选中,如果它包含jang,News,Dawn,则应选中所有三个复选框。
我编写的代码始终选中了最后两个复选框,这是错误的。
我的代码是:
var newspaper = document.forms[0].newspaper;
var a = "Jang,News";
var news = ["Jang", "Dawn", "News"]
for (i = 0; i < news.length; i++)
{
if (a.indexOf(news[i]))
{
newspaper[i].checked = true;
}
}
<input type="checkbox" name="newspaper[]" value="Jang">Jang<br />
<input type="checkbox" name="newspaper[]" value="Dawn">Dawn<br />
<input type="checkbox" name="newspaper[]" value="News">The News
如果您只想使用Javascript进行操作,则必须对代码进行一些更改:
将所有复选框的名称更改为“报纸”(不带方括号)
<input type="checkbox" name="newspaper" value="Jang"/>Jang<br />
<input type="checkbox" name="newspaper" value="Dawn"/>Dawn<br />
<input type="checkbox" name="newspaper" value="News"/>The News
检查indexOf返回值不等于-1:
if (a.indexOf(news[i]) != -1) {
newspaper[i].checked = true;
}
这是工作示例 。
var newspaper = document.forms[0]["newspaper[]"];
var a = "Jang,News";
for (i = 0; i < newspaper.length; i++)
{
if(a.indexOf(newspaper[i].value) > -1){
newspaper[i].checked = true;
}
}
是的,我将检查您的代码以及元素的名称。 但是在这里,这可行。
尝试这个-
var newspaper = document.forms[0].newspaper;
var a = "Jang,News";
var news = ["Jang","Dawn", "News"]
for (i = 0; i < news.length; i++)
{
if (a.indexOf(news[i]) != 1)
{
newspaper[i].checked = true;
}
}
小提琴 : -http : //jsfiddle.net/um0y5wrp/9/
请更改代码,并替换为:
if (a.indexOf(news[i]))
{newspaper[i].checked = true;
}
通过:
for(j = 0; j < newspaper.length; j++){
if(newspaper[j].value == newspaper[i].value){
if (a.indexOf(news[i])){
newspaper[j].checked = true;
}
}
}
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