string 如何使用javascript在文本框中设置最小和最大字符长度
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How to set min and max character length in a textbox using javascript
提问by cala
If I have a text and I only want to allow the user enter text between 5 and 10 characters long, how do I do this using javascipt?
如果我有一个文本并且我只想允许用户输入 5 到 10 个字符长的文本，我该如何使用 javascipt 来做到这一点？
I have tried using mixand maxfunctions but they only works for numeric data.
我试过使用mix和max函数，但它们只适用于数字数据。
回答by rboling
You could do something like this:
你可以这样做：
`
`
function checkLength(){
var textbox = document.getElementById("textbox");
if(textbox.value.length <= 10 && textbox.value.length >= 5){
alert("success");
}
else{
alert("make sure the input is between 5-10 characters long")
}
}
</script>
<input type="text" id="textbox"></input>
<input type="submit" name="textboxSubmit" onclick="checkLength()" />
`
回答by njfife
You need to use the maxlength attribute for input fields, something like this should do it:
您需要对输入字段使用 maxlength 属性，应该这样做：
<input name="myTextInput" type="text" maxlength="5"></input>
回答by hemanth
You can use "maxlength" attribute to not allow more than x characters & do validation using javascript for min length.
您可以使用“maxlength”属性不允许超过 x 个字符并使用 javascript 验证最小长度。
see this example: http://jsfiddle.net/nZ37J/
看这个例子：http: //jsfiddle.net/nZ37J/
HTML
HTML
<form id="form_elem" action="/sdas" method="post">
<input type="text" id="example" maxlength="10"></input>
<span id="error_msg" style="color:red"></span>
<input type="button" id="validate" value="validate"></input>
</form>
Javascript:
Javascript：
$("#validate").click(function(){
var inputStr = $("#example").val();
if(inputStr.length<5)
$("#error_msg").html("enter atleast 5 chars in the input box");
else
$("#form_elem").submit();
})
回答by Marc F
I did a bit of a mix of the samples above trying to make it as simple as possible and avoid unnecessary alerts. Script:
我对上面的示例进行了一些混合，试图使其尽可能简单并避免不必要的警报。脚本：
function checkLength(){
var textbox = document.getElementById("comment");
if(textbox.value.length <= 500 && textbox.value.length >= 5){
return true;
}
else{
alert("Your comment is too short, please write more.");
return false;
}
}
code in the form field would be: onsubmit="return checkLength();">
表单字段中的代码将是： onsubmit="return checkLength();">
And the text area in the form itself:
以及表单本身的文本区域：
<label for="comment">*Comment:</label>
<textarea name="comment" id="comment" rows="4" cols="40" required="required"></textarea>
hope this helps!
希望这可以帮助！
回答by Delbin Thomas
<input name="myTextInput" type="text" minlength="5" maxlength="10"></input>
This would do the trick if you do not want to trouble with js.
如果你不想给 js 带来麻烦，这会奏效。
