textarea 控制输入字符字节数(示例代码)_javascript技巧

按字符数控制：

onkeyup="if(this.value.length>2000) this.value=this.value.substr(0,2000)"<br> onkeydown="if(this.value.length>2000) this.value=this.value.substr(0,2000)"<br> onblur="if(this.value.length>2000) this.value=this.value.substr(0,2000)"<br> onpropertychange= "if(this.value.length>2000) this.value=this.value.substr(0,2000)">

按字节数控制：

onkeydown="key1=this.value;value1 = key1.replace(/[\u4e00-\u9fa5]/g,' ');if(value1.length>500) this.value=this.value.substr(0,500)" <br> onkeyup="key1=this.value;value1 = key1.replace(/[\u4e00-\u9fa5]/g,' ');if(value1.length>500) this.value=this.value.substr(0,500)"<br> onblur="key1=this.value;value1 = key1.replace(/[\u4e00-\u9fa5]/g,' ');if(value1.length>500) this.value=this.value.substr(0,500)" <br> onchange="key1=this.value;value1 = key1.replace(/[\u4e00-\u9fa5]/g,' ');if(value1.length>500) this.value=this.value.substr(0,500)">