Question

我想将.doc的消息更改为.txt。
alert（myvar）显示空警报。

enter code here
 <form>
 <input type="file" id="f1">
<button onclick="myFunction(f1.value)">Try it</button>
 </form>
  <script>
    function myFunction(a) {
      var mystr = a;
      var myarr = mystr.split(".doc");
      var ex= ".txt";
      var myvar = myarr + ex;
      alert(myvar);
       }
</script>

Answer 1

使用str.replace函数

mystr.replace(".doc", ".txt")

Answer 2

你有使用split函数的数组whwn。所以

<script>
    function myFunction(a) {
      var mystr = a;
      var myarr = mystr.split(".doc");
      var ex= ".txt";
      var myvar = myarr[0] + ex;
      alert(myvar);
       }
</script>

Answer 3

您可以执行以下操作

 <input type="file" id="f1">
<input type="button" value="test" onclick="test(f1.value)">


function test(a){
    var file = a;
file = file.split(".");
file = file[0]+".html"; //any extension you want
 alert(file);   
}

Answer 4

function changeExt(s){
    if(s.substring(s.length - 3,s.length) == "doc"){
        var s = s.substring(0,s.length - 3);
        s += "txt";
        return s;
    }
    else{
        return 'bad ext';
    }

}

Answer 5

 <script>
    function myFunction(a) {
      var mystr = a;
      var myarr = mystr.split(".doc")[0];
      var ex= ".txt";
      var myvar = myarr + ex;
      alert(myvar);
       }
</script>

Answer 6

请尝试下面给出的代码。也请按照FIDDLE DEMO
进行操作

In html:
<input type="file" id="f1">
<input type="button" value="myfun" onclick="myFunction(f1.value)">

In js:

window.myFunction = function(a) {
 var file = a;
 file = file.split(".");
 file = file[0]+".txt"; 
 alert(file);

}

Answer 7

请尝试下面给出的代码。也请按照FIDDLE DEMO
进行操作

In html:
<input type="file" id="f1">
<input type="button" value="myfun" onclick="myFunction(f1.value)">

In js:

window.myFunction = function(fileName) {
    var newFileName = fileName.substr(0, fileName.lastIndexOf("."));
    newFileName = newFileName+".txt"; 
     alert(newFileName);   
}

Answer 8

当jquery为我们提供替换字符串及其变量时，为什么选择split函数。这是示例

  var str = "Prabhash Rawat";
  var res = str.replace("Rawat", "Huda");

运行此示例后，此脚本的输出将为

Prabhash Huda

在javascript中拆分功能

8 个答案: