1. 当表单里面只有一个checkbox复选框时,这时候很容易判断checkbox复选框是否被选中,如下实例:

<div id=\"divId\" class=\"divTable\">
<div class=\"tableBody\">
<ul ><li ><input id=\"ck1\" type=\"checkbox\" value=\"501\" ></li></ul>
</div>
</div>
< >
if(document.getElementById(\"ck1\").checked){
    alert(\"checkbox is checked\");
}
</ >

document.getElementById("ck1").checked用于获取id为ck1的复选框的checked属性值,如果为true表示复选框选中,否则没有被选中。

 

2。 当表单里有n个checkbox的时候,我们需要使用js遍历来分别判断每个checkbox复选框checked属性值, 如:

<input type=\"checkbox\" id=\"cashbagSaveYN\" name=\"cashbagSaveYN\" value=\"\" />
<input type=\"checkbox\" id=\"cashbagSaveYN\" name=\"cashbagSaveYN\" value=\"\" />
<input type=\"checkbox\" id=\"cashbagSaveYN\" name=\"cashbagSaveYN\" value=\"\" />
function ifChecked()
{
   var a = document.getElementsByName(\"cashbagSaveYN\"); 
   var n = a.length;
   var k = 0;
   for (var i=0; i<n; i++){
        if(a[i].checked){
            k = 1;
        }
    }
        if(k==0){
        alert(\"请选中Checkbox!\");
        return;
    }
 }

document.getElementsByName("cashbagSaveYN")获取到HTML文档中的所以checkbox,结果为一个数组,数组的元素为每个checkbox对象,然后我们使用for遍历这个数组,分别判断每个checkbox的checked属性值,从而来获取checkbox复选框是否被选中。

 

再看一个实例,该实例也是演示 如何判断checkbox是否被选中的。

<html>
    <form name=\"orderForm\">
      <input type=\"checkbox\" name=\"door4\">4 doors<br>
      <input type=\"checkbox\" name=\"door2\">2 doors<hr>
      <input type=\"button\" value=\"Submit Order\" name=\"orderButton\"  =\"submitOrder()\">
    </form>
    <  language=\" \">
    function submitOrder() {
      if((document.orderForm.door4.checked == true) && (document.orderForm.door2.checked == true)){
        console.log(\"You selected two different door styles. Reselect door style.\");
        document.orderForm.door4.checked = false;
        document.orderForm.door2.checked = false;

      }else if((document.orderForm.door4.checked == false) && (document.orderForm.door2.checked == false)){
        console.log(\"You did not select a door style! Please select a door style.\");
      } else  {
        var alertString = String(\"Order: \");
        if(document.orderForm.door4.checked == true)
          alertString += \"4 doors.\";       
        if(document.orderForm.door2.checked == true)
          alertString += \"2 doors.\";       
        console.log(alertString);
      }
    }
    </ >
</html>
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