Ext.form.TextField.prototype.initValue = function() { if(this.value !== undefined){ this.setValue(this.value); }else if(this.el.dom.value.length > 0){ this.setValue(this.el.dom.value); } this.el.dom.size = this.size; if (!isNaN(this.maxLength) && (this.maxLength *1) > 0 && (this.maxLength != Number.MAX_VALUE)) { this.el.dom.maxLength = this.maxLength *1; } };
然后在用的地方添加maxLength属性
{ xtype: 'textfield', name: 'realname', label: '<span style="color:#ff0000;float:none;">*</span>姓名', labelWidth : '30%', maxLength : 4, placeHolder : '请输入姓名', },