Javascript 无法将参数添加到带有循环的 function

Question

我有一个代码在应用于 html 表时应该做热图：

html表代码：

<table class='table' id='js-datatable' cellspacing="0.9" cellpadding="8" border="1">
    <tr>
        <th align=center style="white-space: nowrap;" bgcolor=grey>product</th>
        <th align=center style="white-space: nowrap;" bgcolor=grey>Jan</th>
        <th align=center style="white-space: nowrap;" bgcolor=grey>Feb</th>
        <th align=center style="white-space: nowrap;" bgcolor=grey>Mar</th>
        <th align=center style="white-space: nowrap;" bgcolor=grey>Apr</th>
        <th align=center style="white-space: nowrap;" bgcolor=grey>May</th>
    </tr>
    <tr class='heatmap-stable'>
        <td align=center>K22</td>
        <td align=center>655$</td>
        <td align=center>365$</td>
        <td align=center>265$</td>
        <td align=center>125$</td>
        <td align=center>36$</td>
    </tr>
    <tr class='heatmap-stable'>
        <td align=center>K52</td>
        <td align=center>90</td>
        <td align=center>50</td>
        <td align=center>120</td>
        <td align=center>80</td>
        <td align=center>190</td>
    </tr>
    <tr class='heatmap-stable'>
        <td align=center>J42</td>
        <td align=center>1267</td>
        <td align=center>1567</td>
        <td align=center>347</td>
        <td align=center>697</td>
        <td align=center>70</td>
    </tr>
    <script src='https://cdn.bootcdn.net/ajax/libs/jquery/2.1.3/jquery.js'></script>
    <script type='text/javascript' src='script.js'></script>
</table>

javascript文件代码：

function clean_formatted_data(str) {
    return parseFloat (str.replace (/([%,$,\,])+/g, ''));
}

function col_to_array(tbl_col, target) {
    // Returns column `n` (zero indexed) in table id `target` as an array

    var colArray = $ ('#' + target + ' td:nth-child(' + tbl_col + ')').map (function () {
        return clean_formatted_data ($ (this).text ());
    }).get ();

    return colArray;
}

//------ new schtuff ------------------------//

function get_pos_of_max(col_data) {
    return $.inArray (Math.max.apply (Math, col_data), col_data)
}

function generate_opacities(col_data, max) {
    var opacity_array = [];
    var increment = max / (col_data.length);

    for (i = col_data.length; i >= 1; i--) {
        opacity_array.push (i * increment / 100);
    }

    return opacity_array;
}


function process_col_best_performing(tbl_col, target) {
    var col_data = col_to_array (tbl_col, target);
    var opacity_array = generate_opacities (col_data, 50);
    var row_count = col_data.length;

    for (var i = 1; i <= row_count; i++) {
        $ ('#' + target + ' tr:nth-child(' + (get_pos_of_max (col_data) + 1) + ') td:nth-child(' + tbl_col + ')').css ('background', 'rgba(0,0,255,' + opacity_array[0] + ')');
        col_data[get_pos_of_max (col_data)] = null;
        for (const spliceElement of opacity_array.splice (0, 1)) {

        }

    }
}

假设我有 5 列，所以我的 javascript function 可以这样应用：

process_col_best_performing (tbl_col:1, target:'js-datatable');
process_col_best_performing (tbl_col:2, target:'js-datatable');
process_col_best_performing (tbl_col:3, target:'js-datatable');

但是因为这只是一个例子，真正的 html 表可以有任意数量的列，我想用 for 循环来做这个，我尝试了下面的代码，但它不起作用

var cols_qty = document.getElementById ('js-datatable').rows[0].cells.length
var i;
for(i = 1; i < 4; i++) {
    console.log(i)
    process_col_best_performing(tbl_col=i,'js-datatable');
}

*我是javascript的新手，所以如果你知道答案，请尽可能用最简单的方式解释。

Answer 1

不确定这是否有帮助，但试试下面的代码，第一件事不要声明为 global var i; 在 for 循环之前，我不确定您是否在代码中执行相同的操作，但是相同的 i 在 function 内部发生了变化，并影响了您调用 process_col_best_performing 的循环。 检查下面的代码，看看这是否有意义。

 var cols_qty = document.getElementById ('js-datatable').rows[0].cells.length for(var i = 1; i < 4; i++) { console.log(i) process_col_best_performing(i,'js-datatable'); } function clean_formatted_data(str) { return parseFloat (str.replace (/([%,$,\,])+/g, '')); } function col_to_array(tbl_col, target) { // Returns column `n` (zero indexed) in table id `target` as an array var colArray = $ ('#' + target + ' td:nth-child(' + tbl_col + ')').map (function () { return clean_formatted_data ($ (this).text ()); }).get (); return colArray; } //------ new schtuff ------------------------// function get_pos_of_max(col_data) { return $.inArray (Math.max.apply (Math, col_data), col_data) } function generate_opacities(col_data, max) { var opacity_array = []; var increment = max / (col_data.length); for (var i = col_data.length; i >= 1; i--) { opacity_array.push (i * increment / 100); } return opacity_array; } function process_col_best_performing(tbl_col, target) { var col_data = col_to_array (tbl_col, target); var opacity_array = generate_opacities (col_data, 50); var row_count = col_data.length; for (var i = 1; i <= row_count; i++) { $ ('#' + target + ' tr:nth-child(' + (get_pos_of_max (col_data) + 1) + ') td:nth-child(' + tbl_col + ')').css ('background', 'rgba(0,0,255,' + opacity_array[0] + ')'); col_data[get_pos_of_max (col_data)] = null; for (const spliceElement of opacity_array.splice (0, 1)) { } } }

 <script src='https://cdn.bootcdn.net/ajax/libs/jquery/2.1.3/jquery.js'></script> <table class='table' id='js-datatable' cellspacing="0.9" cellpadding="8" border="1"> <tr> <th align=center style="white-space: nowrap;" bgcolor=grey>product</th> <th align=center style="white-space: nowrap;" bgcolor=grey>Jan</th> <th align=center style="white-space: nowrap;" bgcolor=grey>Feb</th> <th align=center style="white-space: nowrap;" bgcolor=grey>Mar</th> <th align=center style="white-space: nowrap;" bgcolor=grey>Apr</th> <th align=center style="white-space: nowrap;" bgcolor=grey>May</th> </tr> <tr class='heatmap-stable'> <td align=center>K22</td> <td align=center>655$</td> <td align=center>365$</td> <td align=center>265$</td> <td align=center>125$</td> <td align=center>36$</td> </tr> <tr class='heatmap-stable'> <td align=center>K52</td> <td align=center>90</td> <td align=center>50</td> <td align=center>120</td> <td align=center>80</td> <td align=center>190</td> </tr> <tr class='heatmap-stable'> <td align=center>J42</td> <td align=center>1267</td> <td align=center>1567</td> <td align=center>347</td> <td align=center>697</td> <td align=center>70</td> </tr> </table>