# lvalue

[JS](/web/js.md) ⟩ [statement](/web/js/grammar/statement.md) ⟩ [expression](/web/js/grammar/statement/expr.md) ⟩ [operator](/web/js/grammar/op.md) ⟩ [term](/web/js/grammar/op/term.md) ⟩ lvalue

{% hint style="success" %}
([expression](/web/js/grammar/statement/expr.md)) 

[variable](/web/js/variable.md) <mark style="color:yellow;">**/**</mark> (object) [property](/web/js/val/obj/prop.md) <mark style="color:yellow;">**/**</mark> (array) [element](/web/js/val/builtin/arr/element.md) that appears on the <mark style="color:yellow;">**left side**</mark> of an [assignment](/web/js/grammar/op/assign.md).&#x20;

:u6307: <mark style="color:yellow;">**synonyms**</mark>： "<mark style="color:purple;">**assignment target**</mark>"
{% endhint %}

{% tabs %}
{% tab title="⭐️ 重點" %}
{% hint style="info" %}
[delete](/web/js/val/obj/prop/create/delete.md) expects its <mark style="color:yellow;">**operand**</mark> to be an <mark style="color:purple;">**lvalue**</mark>, <mark style="color:red;">**if**</mark> it is <mark style="color:red;">**not**</mark>**&#x20;**<mark style="color:yellow;">**an**</mark>**&#x20;**<mark style="color:purple;">**lvalue**</mark>, the operator <mark style="color:yellow;">**takes**</mark>**&#x20;**<mark style="color:red;">**no**</mark>**&#x20;**<mark style="color:yellow;">**action**</mark> and <mark style="color:yellow;">**returns**</mark>**&#x20;**<mark style="color:green;">**true**</mark>.
{% endhint %}

{% hint style="success" %} <mark style="color:purple;">**lvalue**</mark> can be used in [for-of](/web/js/grammar/statement/loop/for/of.md) / [for-in](/web/js/grammar/statement/loop/for/in.md) loop.
{% endhint %}
{% endtab %}

{% tab title="👥 相關" %}

* [LHS reference](/web/js/variable/access/lhs.md)
* <mark style="color:purple;">**lvalue**</mark> can be used in a [for-of](/web/js/grammar/statement/loop/for/of.md) / [for-in](/web/js/grammar/statement/loop/for/in.md) loop.
  {% endtab %}

{% tab title="📗 參考" %}

* [ ] [JavaScript: The Definitive Guide](/web/master/ref/javascript-the-definitive-guide.md) ⟩&#x20;
  * [ ] 4.7.1&#x20;
  * [ ] 4.13.4 The delete Operator
    {% endtab %}

{% tab title="📘 手冊" %}

* [for...in](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in)&#x20;
  * ⟩ [parameters](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in#parameters) (for "assignment target")
    {% endtab %}
    {% endtabs %}


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