How to disable the browser's backspace key in JS

This article mainly introduces how to disable the browser's backspace key in JS. It has a certain reference value. Now I share it with you. Friends in need can refer to it.

We are developing real projects JS is often used to disable some keys on the keyboard, such as the backspace key (backspace/back key). In a project, I encountered the backspace key being disabled when editing the page, because the backspace key was disabled. The space key will cause the page to regress, and the edited content will be lost, which is very disgusting. ok, stop talking nonsense and get straight to the code.

  <script>
        //处理键盘事件 禁止后退键（Backspace）密码或单行、多行文本框除外
        function forbidBackSpace(e) {
            var ev = e || window.event; //获取event对象 
            var obj = ev.target || ev.srcElement; //获取事件源 
            var t = obj.type || obj.getAttribute(&#39;type&#39;); //获取事件源类型 
            //获取作为判断条件的事件类型 
            var vReadOnly = obj.readOnly;
            var vDisabled = obj.disabled;
            //处理undefined值情况 
            vReadOnly = (vReadOnly == undefined) ? false : vReadOnly;
            vDisabled = (vDisabled == undefined) ? true : vDisabled;
            //当敲Backspace键时，事件源类型为密码或单行、多行文本的， 
            //并且readOnly属性为true或disabled属性为true的，则退格键失效 
            var flag1 = ev.keyCode == 8 && (t == "password" || t == "text" || t == "textarea") && (vReadOnly == true || vDisabled == true);
            //当敲Backspace键时，事件源类型非密码或单行、多行文本的，则退格键失效 
            var flag2 = ev.keyCode == 8 && t != "password" && t != "text" && t != "textarea";
            //判断 
            if (flag2 || flag1) return false;
        }
        //禁止后退键 作用于Firefox、Opera
        document.onkeypress = forbidBackSpace;
        //禁止后退键  作用于IE、Chrome
        document.onkeydown = forbidBackSpace;
</script>

How to use: Put the above js code between

and it will be ok

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