javascript - 脚本产生我找不到的错误

Question

最终的目的是返回一个显示下面这句话的页​​面

Once upon a time there was a GENDER named NAME
who had a PET named PET NAME.

<SCRIPT language="JavaScript">

var heroGender, heroName, petType, petName;

heroGender = window.prompt('Is the hero female or male? Enter F or M', 'F');

heroName = window.prompt('What is the hero\'s name?','');

petType = window.prompt('What type of pet does the hero have?','');

petName = window.prompt('What is name of the pet?','');

  document.write('Once upon a time there was a ');

if (heroGender == ('F'))
{
    document.write('girl');
}
else 
{
    document.write('boy');
}

document.write('Once upon a time there was a ' + heroGender + ' named ' + heroName '.''<BR>' +
                                    heroName + ' had a ' + petType + ' called ' + petName + '.');

</SCRIPT>

Answer 1

在您等待书籍的同时!

学习 Mozilla Developer Centre !

一个例子:

Example

固定版本

document.write(
    'Once upon a time there was a ' + heroGender + 
    ' named ' + heroName  + '.' + '<BR>' + heroName + 
    ' had a ' + petType + ' called ' + petName + '.');

破解版

您缺少 + 符号。

document.write(
    'Once upon a time there was a ' + heroGender + 
    ' named ' + heroName /* + */ '.' /* + */ '<BR>' + heroName + 
    ' had a ' + petType + ' called ' + petName + '.');

尝试使用

• Firefox 和 Firebug及其控制台选项卡(按 F12)
• IE9 和内置控制台(按 F12。确保控制台已打开，然后刷新)。
• Chrome 和控制台中的构建(按 Ctrl+Shift+J)

观察任何错误信息。

如果这样太费力，那就试试

window.onerror = function(e) {
  alert(e.message);
}

这是一个“改进的”更符合标准的版本。 Example Link!

HTML:

<label> Your Hero's gender </label><input id="heroGender"/><br/>
<label> Your Hero's name </label><input id="heroName"/><br/>
<label> Your Hero's pet type </label><input id="petType"/><br/>
<label> Your Hero's pet name </label><input id="petName"/><br/>
<button> Make me a hero! </button>
<div id="output"></div>

JavaScript:

// make your hero when you press the button
document.getElementsByTagName("button")[0].addEventListener("click", function() {
    // get all the values from the text boxes
    var gender = document.getElementById("heroGender").value,
        name = document.getElementById("heroName").value,
        petType = document.getElementById("petType").value,
        petName = document.getElementById("petName").value;

    // set the text on your output.
    document.getElementById("output").textContent = 
        "Once upon a time there was a " + gender +
        " named " + name + ". " + name + " had a pet " + 
        petType + " called " + petName;


}, false);

上面的代码将在 IE8 或更低版本上中断:(。让 JavaScript 跨浏览器工作是一件很痛苦的事。

所以我可以在

阅读浏览器的文档

• > Firefox's MDN
• 微软 JavaScript docs和 HTML docs

但这些都不容易阅读或浏览。 visibone BrowserBook 是一个很好的跨浏览器脚本可视化指南。 .

它将显示跨浏览器支持(红色是 firefox，蓝色是 IE):

给它几个月的时间，你就会知道如何舒适地使用所有这些东西。