如何獲得多個1複選框的值，以在JavaScript中總計它？

Question

var bookRate = new Array('The Right to differ', 'Issues In Contemporary Documentary', 'Writing, Directing and Producing', 'Lee Kuan Yew My Lifelong Challenge'); 
var selection = document.rate.checkbox; 
var sum = 0.00 ; 

for (i=0; i<selection.length; i++) 

    if (selection[i].checked == true) 
    alert('Book Name : ' + bookRate[i] + ' \n Price of the book : ' + selection[i].value) 

alert('Total Purchased Books : ' + selection[i].value); 

這是我現在擁有的。

我需要知道如何總計，如果有兩個複選框選中？

此功能只顯示選定的項目。

Answer 1

var bookRate=['The Right to differ', 'Issues In Contemporary Documentary', 'Writing, Directing and Producing', 'Lee Kuan Yew My Lifelong Challenge']; 
var selection=document.rate.checkbox; 
var books=0,sum=0.00; 

for(var i=0;i<selection.length;i++) 
{ 
    if(selection[i].checked) 
    { 
     books++; 
     sum+=(parseFloat(selection[i].value,10) || 0); 
    } 
} 
alert("Total purchased book: "+books+"\nTotal price: "+sum); 

是這樣的？

Answer 2

我有2個在我的HTML表單命名車輛，這樣的複選框， <form action=""> <input type="checkbox" name="vehicle" value="5" onclick="check()">vehicle 1 price<br> <input type="checkbox" name="vehicle" value="4" onclick="check()">vehicle 2 price </form>

和我的JavaScript函數

function check() 
    { 
    var bookRate = new Array('The Right to differ', 'Issues In Contemporary Documentary', 'Writing, Directing and Producing', 'Lee Kuan Yew My Lifelong Challenge'); 
    var selection = document.getElementsByName('vehicle'); 
    var sum = 0.00 ; 

for (i=0; i<selection.length; i++) 
    { 
    if (selection[i].checked == true) 
    { 
    sum=sum + parseInt(selection[i].value); 

} 
} 
    alert('Total sum of Purchased Books : ' + sum); 


}