个逗号 如这段代码
注意最后个逗号按语言学角度来说应该是不错
(python类似数据类型辞典dictionary就允许如此)
IE会报语法
但语焉不详你只能用人眼从几千行代码中扫描 <script>
var theObj = {
city : "Boston",
state : "MA",
}
</script>
2. this
引用会改变 如这段代码:
<input type="button" value="Gotcha!" id="MyButton" >
<script>
var MyObject = function
{ this.alertMessage = "Javascript rules";
this.ClickHandler = function
{ alert(this.alertMessage );
}
}
; document.getElementById(”theText”).onclick = MyObject.ClickHandler
</script>
并不如你所愿
答案并不是”JavaScript rules”在执行MyObject.ClickHandler时代码中红色这行this引用实际上指向是document.getElementById("theText")引用可以这么解决: <input type="button" value="Gotcha!" id="theText" >
<script>
var MyObject = function
{ var self = this;
this.alertMessage = “Javascript rules”;
this.OnClick = function
{ alert(self.value);
}
}
; document.getElementById(”theText”).onclick = MyObject.OnClick
</script>
实质上
这就是JavaScript作用域问题如果你看过你会发现解决方案不止种 3. 标识盗贼
在JavaScript中不要使用跟HTML
id样变量名如下代码: <input type="button" id="TheButton">
<script>
TheButton = get("TheButton");
</script>
IE会报对象未定义
我只能说:IE sucks. 4.
串只替换第个匹配 如下代码:
<script>
var fileName = "This is a title".replace(" ","_");
</script>
而实际上
结果是”This_is a title“. 在JavaScript中String.replace第个参数应该是正则表达式所以正确做法是这样: var fileName = "This is a title".replace(/ /g,"_");
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