function underline() {

  var text = document.getElementById("note_header").style.textDecoration;

  if (text == 'normal') {
    document.getElementById("note_header").style.textDecoration = 'Underline';
  } else {
    document.getElementById("note_header").style.textDecoration = 'normal';
  }
}

<input id="btn" type="button" value="Underline" name="btn" onclick="underline()">

最佳答案

normal不是text-decoration的可接受值。请改用none



function underline(){
  var text = document.getElementById("note_header").style.textDecoration;

  if (text !== 'underline'){
    document.getElementById("note_header").style.textDecoration = 'underline';
  } else{
    document.getElementById("note_header").style.textDecoration = 'none';
  }
}

<textarea id="note_header"  rows="3" cols="15">
That's my note
</textarea><br/>
<input id="btn" type="button" value="Underline" name="btn" onclick="underline()">

关于javascript - 为什么JavaScript中的Underline功能不起作用?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/55608558/

10-11 06:39