javascript - How can I truncate the contents of a textarea using JavaScript?

Question

I have a text field, I am using onkeypress to check the length of the entered string. If it exceeds n number of characters it will return false and it will not accept any other character, But Here I am unable to remove the characters I don't want in thetext field. How can I remove the text here.

Answer 1

试试这个，如果你正在使用textarea

<textarea onkeypress="return limitlength(this, 20)" style="width: 300px; height: 90px"></textarea>

 function limitlength(obj, length){
    var maxlength=length
    if (obj.value.length>maxlength)
     obj.value=obj.value.substring(0, maxlength)
 }

Answer 2

使用简单的 HTML5，不需要 javascript：

<input type="text" maxlength="5"/>

MDN

Answer 3

检查 Onkeyup 事件中输入文本的长度。如果它大于 n 则使用子字符串截断前 n 个字符，然后将新字符串设置为值

   $("#mytxt").onkeyup(function(){

 var Currentlength =$(this).val().length;
 var CurrentVal = $(this).val();
 if(Currentlength > n)
 {
  $(this).val(CurrentVal.substring(0,n));
  return false;
 } 
});