我想要输出用*组成的三角形，为什么不能在当前指定的div标签不能显示出来值
请输入要显示的三角形的高度：
<script> <br /> // a总共的行数 document.getElementById("usernameTip").innerHTML="<font color=red>√ 请输入用户名"; <br /> function sanjiaoxing() { <br /> var a=document.getElementById("sanjiao").value; <br /> var number=a-0; <br /> // document.getElementById("sj").innerHTML=number; <br /> if(number==NaN){ <br /> <br /> document.getElementById("sj").innerHTML="此值不是数字，请输入数字"; <br /> return false; <br /> } <br /> else{ <br /> var n=1;// 第n行 <br /> <br /> for(;a>0;a--){ <br /> for(var b=1;b<a;b++){ <br /> document.getElementById("sj").innerHTML=" "; <br /> } <br /> <br /> for(var c=1;c<=2*n-1;c++){ <br /> document.getElementById("sj").innerHTML=" * "; <br /> } <br /> document.getElementById("sj").innerHTML=""; <br /> n++; <br /> } <br /> // document.write(""); <br /> // document.write(""); <br /> // a总共的行数 <br /> } <br /> } <br /> <br /> </script>
回复讨论(解决方案)
你每次都重新赋值，所以最后那个
覆盖了，应该不用= 而用 += 来连接。
for(;a>0;a--){
for(var b=1;b document.getElementById("sj").innerHTML +=" ";
}
for(var c=1;c document.getElementById("sj").innerHTML +=" * ";
}
document.getElementById("sj").innerHTML +="";
n++;
}
另外你检查是否数字那里有问题。
修改如下：
<html><head><meta charset="utf-8"><title>Document</title><style>input{width:50px;height:40px;}#sj{width:1000px;height: 40px;box-shadow:0 10px 40px skyblue inset;}</style></head><body><div>请输入要显示的三角形的高度：<input type="text" id="sanjiao" name="sanjiao" maxlength="3"/><input type="submit" value="提交" onclick="return sanjiaoxing()"/></div><div id="sj"></div><script type="text/javascript"> // a总共的行数 document.getElementById("usernameTip").innerHTML="<font color=red>√ 请输入用户名</font>"; function sanjiaoxing() { var a=document.getElementById("sanjiao").value; // document.getElementById("sj").innerHTML=number; if(/^\d+$/.test(a)==false){ document.getElementById("sj").innerHTML="此值不是数字，请输入数字"; return false; }else{ var n=1;// 第n行 document.getElementById("sj").innerHTML = ""; for(;a>0;a--){ for(var b=1;b<a;b++){ document.getElementById("sj").innerHTML +=" "; } for(var c=1;c<=2*n-1;c++){ document.getElementById("sj").innerHTML+=" * "; } document.getElementById("sj").innerHTML+="</br>"; n++; } // document.write("</br>"); // document.write("</br>"); // a总共的行数 } } </script></body></html>
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