Javascript 如何从javascript更新输入文本？
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How to update an input text from javascript?
提问by anand
I have this simple code that speaks for itself.Here it is:
我有这个不言自明的简单代码。它是：
<script language='javascript">
function check() {}
</script>
<div id="a">input type="text" name="b">
<input type="button" onClick=" check(); ">
All i want is that when i press the button, the text field gets a value updated to it.
我想要的是，当我按下按钮时，文本字段会更新一个值。
I tried using b.value=" C " but it doesnt seem to work.
我尝试使用 b.value=" C " 但它似乎不起作用。
回答by Marcos Placona
<script language="javascript">
function check() {
document.getElementById('txtField').value='new value here'
}
</script>
<input id="txtField" type="text" name="b"> <input type="button" onClick=" check(); ">
This will do. I gave it an ID, and used getElementById('txtField') using the id, and updated it's value.
这会做。我给了它一个 ID，并使用该 ID 使用 getElementById('txtField')，并更新了它的值。
回答by Robusto
You seem to be thinking that giving a form input a name attribute makes it addressable as though it were a global variable. It doesn't. There is a syntax for that, and you would have to use something like:
您似乎在想，给表单输入一个 name 属性使其可寻址，就好像它是一个全局变量一样。它没有。有一个语法，你必须使用类似的东西：
document.forms[0].b.value = "C";
in order to get to address it successfully. You areputting your form elements inside a form, aren't you?
以便成功解决它。你是把你的窗体元素里面，不是吗？
Do it that way, or use an ID along with the getElementById method, as mplacona suggests.
按照 mlacona 的建议，这样做，或者将 ID 与 getElementById 方法一起使用。
