Question

欢迎

当用户点击我的代码中的每个按钮时，我需要显示一个警告框

示例：用户单击H按钮..警报必须显示H字母

这是代码

  var key = [["q","w","e","r","t","y","u","i","o","p"], ["a","s","d","f","g","h","j","k","l"], ["z","x","c","v","b","n","m"]];

  for(var i = 0; i < key.length; i++)


  function printchar()

      alert("here how i can print the letter i was clicked ?")



    document.write("<div>");
    for(var j = 0; j < key[i].length; j++)

       document.write("<input type='button' onclick='printchar()' value='" + key[i][j] + "'/>");

    document.write("</div>");

Answer 1

一个简短的方法是使用forEach遍历数组并创建按钮，将onclick添加到每个新创建的按钮。

var keys=['A','B','Z'];
keys.forEach(function(key){
    var btn=document.createElement('button');
    btn.onclick=function(){alert(this.innerHTML);};
   btn.innerHTML=key;
   document.body.appendChild(btn);
 });

Answer 2

如果你不想完全重新设计你的解决方案（顺便说一句，它缺少一堆花括号），你可以将这封信作为参数传递给你的printchar函数。 ..

for(var j = 0; j < key[i].length; j++){
    document.write("<input type='button' onclick='printchar(\"" + key[i][j] + "\")' value='" + key[i][j] + "'/>");
}

function printchar(letter){
    alert(letter);
}

或者，您可以使用事件和closures来避免将JavaScript插入HTML字符串中：

key[i].forEach(function(currentKey){
    var btn = document.createElement('input');
    btn.value = currentKey;
    btn.onclick = function(){
        alert(currentKey);
    }
    // ... now insert btn somewhere on the page
});

Answer 3

以下是使用您的代码的工作解决方案，以及一些更改：

  var key = [["q","w","e","r","t","y","u","i","o","p"],["a","s","d","f","g","h","j","k","l"], ["z","x","c","v","b","n","m"]];

  function printchar(letter) {
      alert(letter);
  }

  for(var i = 0; i < key.length; i++) {
    document.write("<div>");
    for(var j = 0; j < key[i].length; j++) {
       document.write("<input type='button' onclick='printchar(this.value);' value='" + key[i][j] + "'/>");
       document.write("</div>");
    }
  }

更改包括：

在{函数和}循环

printchar

for

将所选按钮的值传递到printchar函数（作为letter）

我如何打印字母用户点击javascript？

3 个答案: