javascript jQuery .val() 在设置变量时不起作用
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jQuery .val() not working when setting a variable
提问by geoffs3310
If i have an input like so:
如果我有这样的输入：
<input type="text" id="textvalue" />
the following code will change its value:
以下代码将更改其值：
$(document).ready(function() {
$('#textvalue').val("hello");
});
however the following will not work:
但是以下方法不起作用：
$(document).ready(function() {
var = "hello";
$('#textvalue').val(var);
});
Why does the second one not work? I need to be able to change the value of the textbox to the value of a variable
为什么第二个不起作用？我需要能够将文本框的值更改为变量的值
回答by Loktar
Your varstatement needs to look something like this
你的var陈述需要看起来像这样
var something = "hello"
$('#textvalue').val(something );
Right now your not actually assigning a value to a variable, and then you are trying to use the varkeyword.
现在您实际上并没有为变量赋值，然后您正在尝试使用var关键字。
回答by David says reinstate Monica
varis a reserved word, which means it can't be used as a variable name. If you try:
var是一个保留字，这意味着它不能用作变量名。如果你试试：
var variable = "hello";
$('#textvalue').val(variable);
it would work.
它会工作。
Just for interest: varis used to declarevariables, as above.
只是为了兴趣：var用于声明变量，如上。
回答by Eric Allen
var is a reserved word in JavaScript because you use it to declare a variable and you are therefore declaring an empty variable.
var 是 JavaScript 中的保留字，因为您使用它来声明一个变量，因此您声明的是一个空变量。
Use this:
用这个：
$anything = "hello";
$('#textvalue').val($anything);
Obviously you can replace anything with whatever you want, just don't use var.
显然你可以用你想要的任何东西替换任何东西，只是不要使用 var。
Naming conventions are pretty important, you should have a meaningful name for each variable, ideally.
命名约定非常重要，理想情况下，每个变量都应该有一个有意义的名称。
回答by yojimbo87
Try this:
试试这个：
$(document).ready(function() {
var myHello = "hello";
$('#textvalue').val(myHello);
});
You have to assign your text to a variable with name. var itself is a keyword.
您必须将文本分配给具有名称的变量。var 本身是一个关键字。
