How to use JavaScript and CSS to change the color of text between lines_javascript skills

Let’s look at a simple method first.
Define two styles in css .odd{...} and .even{...} for different background colors of odd-numbered rows and even-numbered rows respectively. After the web page is loaded, use javascript to obtain the list of tags to be changed, and execute the following code:

// 当文件加载时，执行代码。
window.onload = function() {
 // 获取<ul id="list" />对象
 var list = document.getElementById('list');
 // 获取list下面的所有li
 var items = list.getElementsByTagName('li');
 // 遍历items
 for (var i = 0; i < items.length; i++) {
  var className = (i % 2 == 0) &#63; ' odd' : ' even';
  items[i].className += className; 
 }
}

Implementing different colors for different rows, so that the change is completely processed on the front end and will not be confused with the back-end logic, which is a better solution.
Then the effect of implementing this code is basically as follows:

However, there are some problems with this approach:

• Only one specified list can be rendered and cannot be reused
• You cannot specify the starting position of discoloration. When processing the discoloration of the table, you have to write a special processing
• The code is all in the onload event, and the dependence on the page is too high

Improve the code and move it into a separate function:

/**
 * 此方法用于列表的隔行变色效果，可以灵活得为指定ID的列表指定隔行的颜色。
 *
 * @param id 列表的id
 * @param item 要变色的行的标签
 * @param odd 奇数行的样式类名，如果不指定，则默认为odd
 * @param even 偶数行的样式类名，如果不指定，则默认为even
 * @param start 开始变色的行的索引，如果不指定，则默认为0
 * @param end 结束变色的行的索引，如果不指定，则默认为列表长度
 */
function rowRender(id, item, odd, even, start, end) {
 // 获取列表容器
 var list = document.getElementById(id);
 // 获取列表
 var items = list.getElementsByTagName(item);
 
 // 修正初始位置，如果不是一个数字或者越界，则从0开始
 if (isNaN(start) || (start < 0 || start >= items.length)) {
  start = 0;
 }
 
 // 修正结束位置，如果不是一个数字或者越界，则为列表末尾
 if (isNaN(end) || (end < start || end >= items.length)) {
  end = items.length;
 }
 
 // 如果没有指定odd，则默认为'odd'
 odd = odd || 'odd';
 // 如果没有指定even, 则默认为'even'
 even = even || 'even'; 
 
 // 遍历列表并渲染效果
 for (var i = start; i < end; i++) {
  var className = ' ' + ((i % 2 == 0) &#63; odd : even);
  items[i].className += className;
 }
}

Usage:

window.onload = function() {
 // 渲梁list1下所有的li标签，使用默认的样式和起始位置
 rowRender('list1', 'li');

 // 渲梁list2下所有的li标签，使用指定的odd和默认的even，使用指定的起始位置
 rowRender('list2', 'li', 'odd1', null, 2, 6);

 // 渲梁table1下所有的tr标签，使用指定的odd和even，使用默认的起始位置
 rowRender('table1', 'tr', 'tr-odd', 'tr-even');
 // 渲梁table2下所有的tr标签，使用指定的odd和even，使用指定的起始位置
 rowRender('table2', 'tr', 'tr-odd', 'tr-even', 1);
}

Example:
Table 1

rowRender('table1', 'tr', 'tr-odd', 'tr-even');

Table 2

rowRender('table1', 'tr', 'tr-odd', 'tr-even', 1);