哪些浏览器目前支持JavaScript的“let”关键字？ [英] What browsers currently support JavaScript's 'let' keyword?

问题描述

我正在开发一个应用程序，不必担心Internet Explorer，并且正在研究A +级别浏览器中不在Internet Explorer 1中的一些功能。

我想玩的这些功能之一是 JavaScript的let关键字

我似乎无法得到他们的任何'让'的例子在Firefox 3.6 用户代理字符串：Mozilla / 5.0（Windows; U; Windows NT 5.1;美国; rv：1.9.2）Gecko / 20100115 Firefox / 3.6（.NET CLR 3.5.30729））。我得到 SyntaxError：missing;在执行 let foo =bar。





之前的语句支持let关键字？ （或者我做错了什么？）

解决方案

这些扩展不是ECMA-Standard，它们仅受Mozilla实现。

$ b 在浏览器环境中，您应该在脚本标记中包含JavaScript 版本号使用它：

 < script type =application / javascript; version = 1.7> 
 var x = 5; 
 var y = 0; 
 
（x = x + 10，y = 12）{
 alert（x + y +\\\
）; 
} 
 
 alert（（x + y）+\\\
）; 
< / script> 
  

I'm developing an app and don't have to ever worry about Internet Explorer and was looking into some of the features present in A+ grade browsers that aren't in Internet Explorer1.

One of these features I wanted to play around with is JavaScript's let keyword

I can't seem to get any of their 'let' examples to work in Firefox 3.6 (User-Agent string: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6 (.NET CLR 3.5.30729)). I get SyntaxError: missing ; before statement when executing let foo = "bar".

So, what browsers support the let keyword? (Or am I doing something wrong?)

解决方案

Those extensions are not ECMA-Standard, they are supported only by the Mozilla implementation.

On browser environments you should include the JavaScript version number in your script tag to use it:

<script type="application/javascript;version=1.7">  
  var x = 5;
  var y = 0;

  let (x = x+10, y = 12) {
    alert(x+y + "\n");
  }

  alert((x + y) + "\n");
</script>

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