Javascript - 从字符串获取数组值

Question

我想知道是否有任何方法可以根据字符串获取数组的值，并显示数组中的下一个值。

<p id="current">page1</p>

<p id="next"></p>

<script>
var page = ["page1", "page2", "page3", "page4", "page5"];
if(document.getElementById("current") == page[0]){
  document.getElementById("next").innerhtml = page[1]
};
</script>

这就是我的总体想法。然而，这样会出现很多 if 语句，而且看起来不太漂亮。所以我想知道是否有一种方法可以复制这种函数，而不包含太多的 if 语句。

Answer 1

将代码与注释结合起来是一种很好的学习方式:

// This is the list of pages you have.
var pages = ["page1", "page2", "page3", "page4", "page5"];

// We use the innerText attribute of the #current node to find out
// what the current page is as a string.
var current = document.getElementById("current").innerText;

// Use the indexOf method of pages to get the index of the current
// page in the list of pages.
var index = pages.indexOf(current);

// Now, check if there is a next page. We do so by checking if current
// is not the last page in the list, or rather, there is at least one
// more page in the list.
if (index < pages.length - 1) {

  // If so, we set next to that page. Note that you can put an
  // expression for the key when using bracket notation here!
  var next = pages[index + 1];

} else {

  // Otherwise, use other text.
  var next = "No more pages :(";

}

// Now set the innerHTML of the #next node to the value of next.
document.getElementById("next").innerHTML = next;