jQuery 使用 Javascript 动态更改 HTML5 输入元素的“占位符”属性
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Changing the "placeholder" attribute of HTML5 input elements dynamically using Javascript
提问by cemregr
I'm trying to dynamically update the HTML5 placeholderattribute of a text field using jQuery.
我正在尝试placeholder使用 jQuery动态更新文本字段的 HTML5属性。
$("textarea").attr("placeholder", "New placeholder text");
From Firebug, I can observe that the placeholderattribute is indeed changing. But in the rendered textareaelement, it stays the same. Any suggestions?
从 Firebug 中，我可以观察到该placeholder属性确实在发生变化。但在渲染textarea元素中，它保持不变。有什么建议？
采纳答案by Minkiele
If you are using Firebug I can assume you are using Firefox, and Firefox doesn't yet support placeholderattribute in the input fields itself.
如果您使用的是 Firebug，我可以假设您使用的是 Firefox，而 Firefox 尚不支持placeholder输入字段本身的属性。
I just tried on Chrome for Mac and it supports placeholder text on textareas (and changes via javascript)
我刚刚在 Mac 版 Chrome 上尝试过，它支持 textareas 上的占位符文本（并通过 javascript 进行更改）
2015 Update: sometimes I gain reputation for this answer, so I want to clarify that this was accepted as correct because at the time Firefox 3.6 didn't support placeholder attribute. Release 4 then added support ("fixed the issue" wouldn't have been fair) so the code of OP works as expected since then.
2015 年更新：有时我因这个答案而声名鹊起，所以我想澄清一下，这被认为是正确的，因为当时 Firefox 3.6 不支持占位符属性。然后第 4 版添加了支持（“修复了问题”是不公平的），因此 OP 的代码从那时起就按预期工作。
回答by tilak
try this :
尝试这个 ：
$('#inputTextID').attr("placeholder","placeholder text");
回答by xavok
I think you have to do that :
我认为你必须这样做：
$("textarea").val('');
$("textarea").attr("placeholder", "New placeholder text");
回答by NomanJaved
<label for="myname">Name *</label>
<input type="text" name="myname" id="myname" title="Please enter your name"
pattern="[A-Za-z ]+, [A-Za-z ]+"
autofocus required placeholder="Last, First" />
Then you want to select the placeholder and replace that text with the new text that you want to enter.
然后您要选择占位符并将该文本替换为new text that you want to enter.
$("input[placeholder]").attr("placeholder", "This is new text");
This will replace the text of Last, Firstto This is new text.
这将替换Last, Firstto的文本This is new text。
回答by overflow
working example of dynamic placeholder using Javascript and Jquery http://jsfiddle.net/ogk2L14n/1/
使用 Javascript 和 Jquery http://jsfiddle.net/ogk2L14n/1/的动态占位符的工作示例
<input type="text" id="textbox">
<select id="selection" onchange="changeplh()">
<option>one</option>
<option>two</option>
<option>three</option>
</select>
function changeplh(){
debugger;
var sel = document.getElementById("selection");
var textbx = document.getElementById("textbox");
var indexe = sel.selectedIndex;
if(indexe == 0) {
$("#textbox").attr("placeholder", "age");
}
if(indexe == 1) {
$("#textbox").attr("placeholder", "name");
}
}
回答by Yogesh
HTML:
HTML：
<input type="text" placeholder="entername" id="fname"/>
JS:
JS：
$("#fname").attr("placeholder", "New placeholder text");
