javascript 用javascript计算html表中的数字
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calculate numbers in html table with javascript
提问by Laziale
I am working on a project where I need to calculate some numbers in html table with javascript. The user can add as much numbers as they need and once they click a button, they'll need to see the end sum. I would like to know how I can do that with javascript, you can find the code below:
我正在做一个项目，我需要用 javascript 计算 html 表中的一些数字。用户可以根据需要添加任意数量的数字，一旦他们单击按钮，他们将需要查看最终总和。我想知道如何使用 javascript 做到这一点，您可以在下面找到代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Javascript Calculator</title>
<SCRIPT language="javascript">
function Calculate()
{
}
function addRow()
{
var table = document.getElementById('table');
var button = document.getElementsByTagName('input')[0];
button.onclick = function() {
var clone = table.rows[table.rows.length - 2].cloneNode(true);
clone.cells[0].firstChild.data =
clone.cells[0].firstChild.data.replace(/(\d+):/,function(str,g1) {
return (+g1 + 1) + ':';
});
table.tBodies[0].appendChild(clone);
};
}
</SCRIPT>
</head>
<input type=button value='Add Row' onclick="addRow()" />
<br /><br />
<table cellspacing=0 cellpadding=4 id="table">
<tbody>
<tr><td>Number 1:</td><td><input value=20 style="width:30px" type=text maxlength=2/></td></tr>
<tr><td>Number 2:</td><td><input value=25 style="width:30px" type=text maxlength=2/></td></tr>
</tbody>
<tfoot>
<tr><td style="border-top:solid 1px black;border-bottom:solid 1px black;">Sum:</td><td style="border-top:solid 1px black;border-bottom:solid 1px black;"><div>45</div></td></tr>
</tfoot>
</table>
<input type=button value='Recalculate Sum' onclick="Calculate()" />
</body>
</html>
Any idea how I can solve this? Thanks in advance, Laziale
知道我该如何解决这个问题吗？提前致谢， Laziale
回答by Brigand
You can loop through each input element in the table and grab the value.
您可以遍历表中的每个输入元素并获取value.
function Calculate() {
var table = document.getElementById('table');
var items = table.getElementsByTagName('input');
var sum = 0;
for(var i=0; i<items.length; i++)
sum += parseInt(items[i].value);
var output = document.getElementById('sum');
output.innerHTML = sum;
}
demo
演示
The only change I made to the HTML was giving an ID to the output div.
我对 HTML 所做的唯一更改是为输出 div 提供了一个 ID。
<div id="sum">45</div>
回答by caleb
use this to grab the inputs
使用它来获取输入
var inputs = document.getElementsByTagName('input');
this will grab all the inputs's, not just 'text' inputs, so you'll want to use something like this in the loop
这将获取所有输入，而不仅仅是“文本”输入，因此您需要在循环中使用类似的内容
if(inputs[i].type == 'text')
total = total + parseInt(inputs[i].value);
and set the value like this
并像这样设置值
document.getElementById('displaySum').innerHTML = total;
