如何从文本框中获取字符串并用javascript在页面中显示

How to get string from text box and display in page in javascript

本文关键字：javascript 显示 串并 字符 文本 获取 字符串      更新时间：2023-09-26

我是javascript的新手，我有一个函数可以获取文本框值并将其返回，但我不能在函数之外使用返回值。我希望函数返回一个字符串并将其显示在网页中。下面是代码。

<%@ page import="java.io.*,java.util.*,java.sql.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql"%>
<!DOCTYPE html>
<html>
<head>
<title> Inventory test </title>
</head>
<body>
<script type="text/javascript">
function function1(){
     var x = document.getElementById("text1").value;
     if (x.length == ""){
         alert ( "input is empty");
     }else{
         alert ( x + " " + "fine"); 
         return x;
     }
 }
</script>
First name: <input type="text" id="text1" name="text1" autofocus>
<button onclick="function1()"> submit </button>
<p id="p1">p1</p> 

</body>
</html>

不返回，而是直接分配您想要的内容，例如，使用

document.getElementById("p1").innerHTML = x

您应该设置dom元素的文本输入值

function function1() {
    document.getElementById("p1").innerHTML = document.getElementById("text1").value;
}

function function1()
{
 var x = document.getElementById("text1").value;
  if (x.length == "")
   {
    alert ( "input is empty");
   }
    else
   {
     alert ( x + " " + "fine"); 
   document.getElementById("p1").innerHTML = x;
 }

试试这个

<%@ page import="java.io.*,java.util.*,java.sql.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql"%>
<!DOCTYPE html>
<html>
<head>
<title> Inventory test </title>
</head>
<body>
<script type="text/javascript">
function function1(){
     var textValue = document.getElementById("text1").value;
     if (x.length == ""){
         alert ( "input is empty");
     }else{
         document.getElementById("p1").innerHTML = textValue;
     }
 }
</script>
First name: <input type="text" id="text1" name="text1" autofocus>
<button onclick="function1()"> submit </button>
<p id="p1">p1</p> 

</body>
</html>
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