javascript: Make form text box read-only, non-editable method

Sometimes, we want the text box in the form to be read-only, so that the user cannot modify the information in it, such as making <input type= "text" name= "INPUT1" value= "China" >, "China" two words can not be modified. The way to achieve is summed up, there are several.

Method 1:onfocus=this.blur ()
<input type= "text" name= "INPUT1" value= "China" Onfocus=this.blur () >

Method 2:readonly
<input type= "text" name= "INPUT1" value= "China" readonly>

<input type= "text" name= "INPUT1" value= "China" readonly= "true" >

Method 3:disabled
<input type= "text" name= "INPUT1" value= "China" disabled>

javascript: Make form text box read-only, non-editable method