textarea计算输入字符大小并限制输入

[html] view plaincopy

1. <textarea class="textarea" id="jqnr" onpropertychange="checkLength(this,800);" oninput="checkLength(this,800);">${params.bz}</textarea>  

[javascript] view plaincopy

1. function checkLength(obj,maxlength){  
2.         if(obj.value.length > maxlength){  
3.             obj.value = obj.value.substring(0,maxlength);  
4.         }  
5.     }