javascript - 行列式计算javascript

Question

我有一些 javascript 和 html 代码，我想显示矩阵行列式的计算值，但该函数不想在输入位置显示它，我希望它显示在哪里，而是我得到一个空格。 HTML

<div id = "table">
<div id = "header">Wyznacznik [3x3]</div>
 <form id = "row1">
    <input type = "text" class = "det"/><!--first row-->
    <input type = "text" class = "det"/>
    <input type = "text" class = "det"/>
 </form>
 <form id = "row2">
    <input type = "text" class = "det"/><!--second row-->
    <input type = "text" class = "det"/>
    <input type = "text" class = "det"/>
</form>
<form id = "row3">
    <input type = "text" class = "det"/><!--third row-->
    <input type = "text" class = "det"/>
    <input type = "text" class = "det"/>
</form>
<div class = "count" onclick="det(3)"><a href = "#">Wylicz</a></div>
<input type = "text" id = "calcValue"/>
</div>

javascript

function det(size){
var arr = document.getElementsByClassName('det1');
var determinant = 0;
if(size == 2){
determinant = (arr[0].value*arr[3].value) - (arr[1].value*arr[2].value);
document.getElementById('calcValue1').value = determinant;
}
else if(size == 3){
determinant = (arr[0].value*((arr[4].value*arr[8].value) - (arr[5].value *   arr[7].value))) - 
(arr[1].value*((arr[3].value*arr[8].value) - (arr[5].value * arr[6].value))) +
(arr[2].value*((arr[3].value*arr[7].value) - (arr[4].value * arr[6].value))); 
document.getElementById('calcValue').value = determinant;
}
return determinant;
}

Answer 1

你没有得到任何元素，试试这个：

var arr = document.getElementsByClassName('det');