Javascript“document.getElementById"它能代替ID'ed元素中的tes

Javascript "document.getElementById" can it replace test in the ID'ed element?

本文关键字：ed ID tes 元素 document getElementById quot Javascript      更新时间：2023-09-26

只是一个非常快的问题。document.getElementById，它可以替换的文本已经存在于引用的ID?我试着摆弄了一些东西，但似乎没有发生。

我想使用的代码如下:

    <!DOCTYPE HTML>
<html>
<HEAD>
    <script>
        function runNumber(){
            num=(Math.round(Math.random()*9)+2);
            for (i = num; i > 0; i--) {
                for (j = num; j > 1; j--) {
                    document.getElementById("runBox").innerHTML += '1+';
                }
            document.getElementById("runBox").innerHTML += '1 <br>';
            }
        document.getElementById("runBox").innerHTML += 'The answer, of course, is <b>' + num + ' x ' + num + ' = ' + [num*num] + '</b>.<p></p>';
        }
        function sentNumber(num){
            for (i = num; i > 0; i--) {
                for (j = num; j > 1; j--) 
                    {document.getElementById("sentBox").innerHTML += '1+';}
            document.getElementById("sentBox").innerHTML += '1 <br>';
            }
        document.getElementById("sentBox").innerHTML += 'The answer is <b>' + num + ' x ' + num + ' = ' + [num*num] + '</b>.<p></p>';
        }
    </script>
</HEAD>
<BODY onload=runNumber()>
    <p><button onclick="history.go(0)">New Examples</button></p>
    <b>The Square Machine</b>
    <p id="runNumber"></p>
    The square of a number is a literal square.<p> So for calculating the square of <b>number x</b>, write down 1 as many times as the x in a grid (x number of rows and x number of columns, like below).<p> Then add all those numbers together, you will get the square of the number!<p> <b>Remember</b>: the square of any negative number is the same as the square of the positive version of that number.<p> Over time, you should know the squares of numbers 1-20 simply from memory.
    <center><p id="runBox"></p></center>
    Try your own number:
    <select id="sentNum">
         <script>
             for (var i = 2; i<=50; i++)
                {document.write("<option value="+i+"> "+i+" </option>");}
         </script>
    </select>
    <p>
    <p><button onclick="sentNumber(document.getElementById('sentNum').value)">Enter</button></p>
    <center>
        <p id="sentNumber"></p>
        <p id="sentBox"></p>
    </center>
    <p><center>
        <b>To do:</b> Nothing.</br>
        <a href="index.html">Home Page</a></center>
    </p>
</BODY>
</HTML>

您正在修改innerHTML, id是outerHTML的一部分(innerHTML是outerHTML，不包括元素自己的代码)。

在任何情况下，getElementById都没有进行修改，它所做的只是获取元素

我想它的效果和预期的一样。

function sentNumber(num){
        for (i = num; i > 0; i--) {
            for (j = num; j > 1; j--) 
                {document.getElementById("sentBox").innerHTML = '1+';}
        document.getElementById("sentBox").innerHTML += '1 <br>';
        }
    document.getElementById("sentBox").innerHTML += 'The answer is <b>' + num + ' x ' + num + ' = ' + [num*num] + '</b>.<p></p>';
    }
sentNumber(10)
<span id="sentBox"> </span>

<年代> http://fiddle.jshell.net/5npfhecs/

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