只是一個非常快速的問題。 document.getElementById
,可以嗎取代已經存在於引用ID中的文字?我嘗試了幾件事,但似乎並沒有發生。Javascript「document.getElementById」可以替代ID'ed元素中的測試嗎?
,我想用這個的代碼如下:
<!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>
顯示HTML也是如此。在運行之前,您還沒有清除innerHTML,j for循環似乎毫無意義。你應該能夠在if語句中處理它。 – Vince
我剛纔把整個頁面的代碼放到上面的原文中。感謝您花時間。 – Jehangir
for j循環打印數字的正方形的行,所以它是一個整齊的正方形。這個想法是向學生展示一個數字的正方形是一個字面正方形。 – Jehangir