获取表格的行数和列数

html:

<body>
    <table id="tab">
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
            <td>4</td>
        </tr>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
            <td>4</td>
        </tr>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
            <td>4</td>
        </tr>
    </table>

    <table id="tt">
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
            <td>4</td>
            <td>3</td>
            <td>4</td>
        </tr>
        <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
            <td>4</td>
            <td>3</td>
            <td>4</td>
        </tr>
        
    </table>
</body>

js:

function show(el){
    var oEl = document.getElementById(el); 
    var rows = oEl.rows.length;
    var cells = oEl.rows.item(0).cells.length;
    console.log(rows,cells)
}
show('tab')
show('tt')