Question

所以我单独测试了提示，并且效果很好，但是之后添加文本之后，似乎什么也没有加载。请帮忙。

var myage = parseInt(prompt("enter age ", 30), 10);

if (myage >= 0 && myage <= 10) {
  document.write("myage is between o and 10 <br/>");
}

if (!(myage >= 0 && myage <= 10)) {
  document.write(" myage is not between 0 and 10 <br/>");
}

if (myage >= 80 || myage <= 10) {
  document.write("myage is equal to or above 80 or 10 or less");
}

if ((myage >= 30 && myage <= 39) || (myage >= 80 && <= 89)) {
  document.write("myage is between 30 and 39 or myage is " + "between 80 and 89");

}

Answer 1

在最后一个if语句中，您忘记将我的myage添加到值检查中；您只是编写了<=运算符而没有要比较的变量值。

在调试时应打开控制台。控制台显示“未捕获到的SyntaxError：意外令牌<=，这将导致您转到发生问题的行。

更改

if ((myage >= 30 && myage <= 39) || (myage >= 80 && <= 89/*missing variable to check the value of*/)) {
  document.write("myage is between 30 and 39 or myage is " + "between 80 and 89");

}

收件人

if( (myage>=30 && myage<=39)||(myage>=80&&myage<=89)) {
      document.write ("myage is between 30 and 39 or myage is " + "between 80 and 89");
}

var myage = parseInt ( prompt("enter age ", 30) , 10);

if (myage >= 0 && myage <= 10) {
  document.write("myage is between o and 10 <br/>");
}

if (!(myage >= 0 && myage <= 10 )){
  document.write(" myage is not between 0 and 10 <br/>");
}

if (myage>=80||myage<=10) {
  document.write("myage is equal to or above 80 or 10 or less");
}

if( (myage>=30 && myage<=39)||(myage>=80&&myage<=89)) {
  document.write ("myage is between 30 and 39 or myage is " + "between 80 and 89");
}

Answer 2

您最后一次错过了myage。

var myage = parseInt(prompt("enter age ", 30), 10);

if (myage >= 0 && myage <= 10) {
  document.write("myage is between o and 10 <br/>");
}

if (!(myage >= 0 && myage <= 10)) {
  document.write(" myage is not between 0 and 10 <br/>");
}

if (myage >= 80 || myage <= 10) {
  document.write("myage is equal to or above 80 or 10 or less");
}

if ((myage >= 30 && myage <= 39) || (myage >= 80 && myage <= 89)) {
  document.write("myage is between 30 and 39 or myage is " + "between 80 and 89");

}

添加if语句后，我的“提示”将不会加载到网页上

2 个答案: