IE7中的HTMLInputElement

我正在爲crossbrowser輸入寫一個擴展& textarea選擇getter和setter。所以這是我寫我的代碼的方式：IE7中的HTMLInputElement

HTMLInputElement.prototype.getSelectionRange = get_selection_range; 
HTMLInputElement.prototype.setSelection = set_selection_range; 
HTMLTextAreaElement.prototype.getSelectionRange = get_selection_range; 
HTMLTextAreaElement.prototype.setSelection = set_selection_range;

get_selection_range和set_selection_range是這些擴展功能。所以，我只是想取代

someInputElement.selectionStart = a; // and whole lot of code due to browser 
someInputElement.selectionEnd = b; // compatibility

只有

someInputElement.setSelection(a, b); 
someInputElement.setSelection({ start: a, end: b }); 
someOtherElement.setSelection(someInputElement.getSelection());

但後來我遇到了幾個困難IE7。首先，IE7不知道什麼是HTMLInputElement。

我不想擴展整個對象。那麼，這將是我會做的最後一件事，但我想逃避它。函數get_selection_range和set_selection_range沒問題，不要問什麼，你已經看過幾次了。

所以問題是：是否有任何合法的替代IE中的JS的HTMLInputElement？

UPD：我做了我自己的解決方案，無需任何擴展全局對象類型：

var SmartInputSelection = Base.extend({ 
    constructor: function (options) { 
     this.node = options.node; 
     this.CHARACTER = "character"; 
     this.END_TO_END = "EndToEnd"; 
     this.END_TO_START = "EndToStart"; 
    }, 
    setSelection: function (a, b) { 
     if (b === undefined && typeof a == "number") 
      b = a; 
     else if (b === undefined) { 
      b = a.end; 
      a = a.start; 
     } 

     if (this.node.selectionStart !== undefined) { 
      this.node.selectionStart = a; 
      this.node.selectionEnd = b; 
     } else { 
      var textRange = this.node.createTextRange(); 
      textRange.collapse(true); 
      textRange.moveStart(this.CHARACTER, a); 
      textRange.moveEnd(this.CHARACTER, b - a); 
      textRange.select(); 
     } 
    }, 
    getSelection: function() { 
     var start, end; 
     if (this.node.selectionStart !== undefined) { 
      start = this.node.selectionStart; 
      end = this.node.selectionEnd; 
     } else { 
      var range = document.selection.createRange(); 
      if (range == null) { 
       start = end = 0; 
      } 

      var textRange = this.node.createTextRange(), 
      duplicate = textRange.duplicate(); 
      textRange.moveToBookmark(range.getBookmark()); 
      duplicate.setEndPoint(this.END_TO_END, textRange); 
      end = duplicate.text.length; 
      duplicate.setEndPoint(this.END_TO_START, textRange); 
      start = duplicate.text.length; 
     } 

     return { 
      start: start, 
      end: end 
     }; 
    } 
});

所以現在我只是要聲明是這樣的：

function SelectSomeTextInsideInput (input /* input is some DOM element */) { 
    var smartInputSelection = new SmartInputSelection({ node: input }); 
    smartInputSelection.setSelection(0); 
    smartInputSelection.setSelection(2, 5); 
    smartInputSelection.setSelection({ start: 2, end: 5 }); 
    smartInputSelection.getSelection(); // start: 2, end: 5 
}

來源

2012-09-11 Vladislav Qulin