不提交

document.onkeydown = function(event) {               var target, code, tag;               if (!event) {                   event = window.event; //针对ie浏览器                   target = event.srcElement;                   code = event.keyCode;                   if (code == 13) {                       tag = target.tagName;                       if (tag == "TEXTAREA") { return true; }                       else { return false; }                   }               }               else {                   target = event.target; //针对遵循w3c标准的浏览器，如Firefox                   code = event.keyCode;                   if (code == 13) {                       tag = target.tagName;                       if (tag == "INPUT") { return false; }                       else { return true; }                    }               }           };   

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