[英]how to check checkboxes in javascript
我在html中有三個復選框。
在Javascript中,我有可變newspaper = "jang,News,Dawn"
;
現在,我想基於報紙的值檢查復選框,如果它僅包含jang,則僅jang復選框應被選中,如果它包含jang,News,Dawn,則應選中所有三個復選框。
我編寫的代碼始終選中了最后兩個復選框,這是錯誤的。
我的代碼是:
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進行操作,則必須對代碼進行一些更改:
將所有復選框的名稱更改為“報紙”(不帶方括號)
<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
檢查indexOf返回值不等於-1:
if (a.indexOf(news[i]) != -1) {
newspaper[i].checked = true;
}
這是工作示例 。
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,我將檢查您的代碼以及元素的名稱。 但是在這里,這可行。
嘗試這個-
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/
請更改代碼,並替換為:
if (a.indexOf(news[i]))
{newspaper[i].checked = true;
}
通過:
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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