textarea 控制输入字符字节数(示例代码)

Javascript教程 2025-08-19

按字符数控制:

复制代码代码如下:

< textarea name="gbContent"

onkeyup="if(this.value.length >2000) this.value=this.value.substr(0,2000)"

onkeydown="if(this.value.length >2000) this.value=this.value.substr(0,2000)"

onblur="if(this.value.length >2000) this.value=this.value.substr(0,2000)"

onpropertychange= "if(this.value.length >2000) this.value=this.value.substr(0,2000)" >< /textarea >

按字节数控制:

复制代码代码如下:

< textarea cols="50" id="description" name="userModel.description" rows="5"

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

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

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

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